Single-nucleus chromatin accessibility profiling highlights distinct astrocyte signatures in progressive supranuclear palsy and corticobasal degeneration

Tauopathies such as progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) exhibit characteristic neuronal and glial inclusions of hyperphosphorylated Tau (pTau). Although the astrocytic pTau phenotype upon neuropathological examination is the most guiding feature in distinguishing both diseases, regulatory mechanisms controlling their transitions into disease-specific states are poorly understood to date. Here, we provide accessible chromatin data of more than 45,000 single nuclei isolated from the frontal cortex of PSP, CBD, and control individuals. We found a strong association of disease-relevant molecular changes with astrocytes and demonstrate that tauopathy-relevant genetic risk variants are tightly linked to astrocytic chromatin accessibility profiles in the brains of PSP and CBD patients. Unlike the established pathogenesis in the secondary tauopathy Alzheimer disease, microglial alterations were relatively sparse. Transcription factor (TF) motif enrichments in pseudotime as well as modeling of the astrocytic TF interplay suggested a common pTau signature for CBD and PSP that is reminiscent of an inflammatory immediate-early response. Nonetheless, machine learning models also predicted discriminatory features, and we observed marked differences in molecular entities related to protein homeostasis between both diseases. Predicted TF involvement was supported by immunofluorescence analyses in postmortem brain tissue for their highly correlated target genes. Collectively, our data expand the current knowledge on risk gene involvement (e.g., MAPT, MAPK8, and NFE2L2) and molecular pathways leading to the phenotypic changes associated with CBD and PSP.

A highly stable monolithic enhancement cavity for second harmonic generation in the ultraviolet

We present a highly stable bow-tie power enhancement cavity for critical second harmonic generation (SHG) into the UV using a Brewster-cut β-BaB₂O₄ (BBO) nonlinear crystal. The cavity geometry is suitable for all UV wavelengths reachable with BBO and can be modified to accommodate anti-reflection coated crystals, extending its applicability to the entire wavelength range accessible with non-linear frequency conversion. The cavity is length-stabilized using a fast general purpose digital PI controller based on the open source STEMlab 125-14 (formerly Red Pitaya) system acting on a mirror mounted on a fast piezo actuator. We observe 130 h uninterrupted operation without decay in output power at 313 nm. The robustness of the system has been confirmed by exposing it to accelerations of up to 1 g with less than 10% in-lock output power variations. Furthermore, the cavity can withstand 30 min of acceleration exposure at a level of 3 g_rms without substantial change in the SHG output power, demonstrating that the design is suitable for transportable setups.

Substitutions of PrP N-terminal histidine residues modulate scrapie disease pathogenesis and incubation time in transgenic mice

Prion diseases have been linked to impaired copper homeostasis and copper induced-oxidative damage to the brain. Divalent metal ions, such as Cu2+ and Zn2+, bind to cellular prion protein (PrPC) at octapeptide repeat (OR) and non-OR sites within the N-terminal half of the protein but information on the impact of such binding on conversion to the misfolded isoform often derives from studies using either OR and non-OR peptides or bacterially-expressed recombinant PrP. Here we created new transgenic mouse lines expressing PrP with disrupted copper binding sites within all four histidine-containing OR's (sites 1-4, H60G, H68G, H76G, H84G, "TetraH>G" allele) or at site 5 (composed of residues His-95 and His-110; "H95G" allele) and monitored the formation of misfolded PrP in vivo. Novel transgenic mice expressing PrP(TetraH>G) at levels comparable to wild-type (wt) controls were susceptible to mouse-adapted scrapie strain RML but showed significantly prolonged incubation times. In contrast, amino acid replacement at residue 95 accelerated disease progression in corresponding PrP(H95G) mice. Neuropathological lesions in terminally ill transgenic mice were similar to scrapie-infected wt controls, but less severe. The pattern of PrPSc deposition, however, was not synaptic as seen in wt animals, but instead dense globular plaque-like accumulations of PrPSc in TgPrP(TetraH>G) mice and diffuse PrPSc deposition in (TgPrP(H95G) mice), were observed throughout all brain sections. We conclude that OR and site 5 histidine substitutions have divergent phenotypic impacts and that cis interactions between the OR region and the site 5 region modulate pathogenic outcomes by affecting the PrP globular domain.

Between-Batch Pharmacokinetic Variability Inflates Type I Error Rate in Conventional Bioequivalence Trials: A Randomized Advair Diskus Clinical Trial

We previously demonstrated pharmacokinetic differences among manufacturing batches of a US Food and Drug Administration (FDA)-approved dry powder inhalation product (Advair Diskus 100/50) large enough to establish between-batch bio-inequivalence. Here, we provide independent confirmation of pharmacokinetic bio-inequivalence among Advair Diskus 100/50 batches, and quantify residual and between-batch variance component magnitudes. These variance estimates are used to consider the type I error rate of the FDA's current two-way crossover design recommendation. When between-batch pharmacokinetic variability is substantial, the conventional two-way crossover design cannot accomplish the objectives of FDA's statistical bioequivalence test (i.e., cannot accurately estimate the test/reference ratio and associated confidence interval). The two-way crossover, which ignores between-batch pharmacokinetic variability, yields an artificially narrow confidence interval on the product comparison. The unavoidable consequence is type I error rate inflation, to ∼25%, when between-batch pharmacokinetic variability is nonzero. This risk of a false bioequivalence conclusion is substantially higher than asserted by regulators as acceptable consumer risk (5%).

Generation and deposition of Aβ43 by the virtually inactive presenilin-1 L435F mutant contradicts the presenilin loss-of-function hypothesis of Alzheimer's disease

As stated by the prevailing amyloid cascade hypothesis, Alzheimer's disease (AD) is caused by the aggregation and cerebral deposition of long amyloid‐β peptide (Aβ) species, which are released from a C‐terminal amyloid precursor protein fragment by γ‐secretase. Mutations in its catalytic subunit presenilin‐1 (PS1) increase the Aβ42 to Aβ40 ratio and are the major cause of familial AD (FAD). An opposing hypothesis states that loss of essential presenilin functions underlies the disease. A major argument for this hypothesis is the observation that the nearly inactive PS1 L435F mutant, paradoxically, causes FAD. We now show that the very little Aβ generated by PS1 L435F consists primarily of Aβ43, a highly amyloidogenic species which was overlooked in previous studies of this mutant. We further demonstrate that the generation of Aβ43 is not due to a trans‐dominant effect of this mutant on WT presenilin. Furthermore, we found Aβ43‐containing plaques in brains of patients with this mutation. The aberrant generation of Aβ43 by this particular mutant provides a direct objection against the presenilin hypothesis.

Direct Observation of Photoinduced Tautomerization in Single Molecules at a Metal Surface

Molecular switches are of fundamental importance in nature, and light is an important stimulus to selectively drive the switching process. However, the local dynamics of a conformational change in these molecules remain far from being completely understood at the single-molecule level. Here, we report the direct observation of photoinduced tautomerization in single porphycene molecules on a Cu(111) surface by using a combination of low-temperature scanning tunneling microscopy and laser excitation in the near-infrared to ultraviolet regime. It is found that the thermodynamically stable trans configuration of porphycene can be converted to the metastable cis configuration in a unidirectional fashion by photoirradiation. The wavelength dependence of the tautomerization cross section exhibits a steep increase around 2 eV and demonstrates that excitation of the Cu d-band electrons and the resulting hot carriers play a dominant role in the photochemical process. Additionally, a pronounced isotope effect in the cross section (∼100) is observed when the transferred hydrogen atoms are substituted with deuterium, indicating a significant contribution of zero-point energy in the reaction. Combined with the study of inelastic tunneling electron-induced tautomerization with the STM, we propose that tautomerization occurs via excitation of molecular vibrations after photoexcitation. Interestingly, the observed cross section of ∼10(-19) cm(2) in the visible-ultraviolet region is much higher than that of previously studied molecular switches on a metal surface, for example, azobenzene derivatives (10(-23)-10(-22) cm(2)). Furthermore, we examined a local environmental impact on the photoinduced tautomerization by varying molecular density on the surface and find substantial changes in the cross section and quenching of the process due to the intermolecular interaction at high density.

Intramedullary pilomyxoid astrocytoma with intracerebral metastasis exhibiting oligoden-droglioma-like features

Intramedullary glioma are rare and their biological behaviour can differ from their cerebral counterparts. Pilomyxoid astrocytoma (PMA, WHO grade II), predominantly occur in the hypothalamic/chiasmatic region of infants and children. The few reported cases of pediatric intramedullary PMA displayed a particularly aggressive behavior. Here, we report a diagnostically challenging case of a five year old female patient presenting with intramedullary glioma and local tumor recurrence three years later. Twelve years after the initial manifestation, a second tumor was found intracerebrally. We performed a comprehensive histological, molecular pathological and imaging analysis of the tumors from both localizations. The results revealed a metastasizing PMA with unique histological and genetic features. Our study indicates that PMA comprise a heterogeneous group including aggressive subtypes which may not be compatible with the current classification according to WHO grade II. Furthermore, the case emphasizes the increasing relevance of molecular pathological markers complementing classic histo-logical diagnosis.

[Dopamine receptors of the corneal epithelium and endothelium]

BACKGROUND

Dopamine is a major neurotransmitter and its two receptor subgroups, termed D1-like and D2-like receptors, are found both in the central and peripheral nervous systems. D1-like receptors signal through increases, D2-like receptors through decreases in cAMP production. Reports about the presence of dopamine receptors in the cornea are rare and inconsistant. The aim of this study was to examine if native bovine corneal epithelial and endothelial cells express dopamine receptors and whether these receptors belong to the D1-like or D2-like group.

MATERIALS AND METHODS

Dopamine receptors were studied using polyclonal antibodies. The cAMP concentration after receptor stimulation with dopamine was determined by means of an enzyme immunoassay.

RESULTS

In bovine corneal epithelium and endothelium immunohistochemical staining was positive for D1-like receptors but not for D2-like receptors. Stimulation of corneal D1-like receptors with dopamine revealed a dose-dependent increase of the intracellular cAMP concentration which was blocked by SCH23 390 (a selective D1-like antagonist).

CONCLUSION

Our data demonstrate that bovine corneal epithelium and endothelium express a functional D1-like receptor positively coupled to adenylyl cyclase and cAMP production. However, at the present time the physiological role of this receptor remains a matter of speculation.

[m4 muscarinic receptors of the cornea : muscarinic cholinoceptor-stimulated inhibition of the cAMP-PKA pathway in corneal epithelial and endothelial cells]

BACKGROUND

Muscarinic cholinoceptors have been found in all types of ocular tissue, e.g. in corneal epithelium and endothelium. Latest research has focused only on the m5 cholinoceptor subtype. However, previous studies have also indicated the presence of m2 or m4 receptor subtypes in corneal tissue. The aim of this study was to show the decrease of intracellular cAMP formation and protein kinase A (PKA) activity after stimulation of m2 or m4 cholinoceptors in bovine corneal epithelial and endothelial cells. MATERIALS UND METHODS: Muscarinic cholinoceptors were studied using polyclonal antibodies. The cAMP concentration was determined with an enzyme immunoassay and PKA activity was estimated by the consumption of ATP.

RESULTS

Immunocytochemistry, immunofluorescence and immunoblotting revealed the presence of the m4 muscarinic cholinoceptor subtype but not of the m2 receptor subtype in bovine corneal epithelial and endothelial cells. In bovine corneal epithelium and endothelium protein cAMP formation was decreased and PKA activity was inhibited by acetylcholine in a dose-dependent manner (p<0.001).

CONCLUSION

The findings indicate that stimulation of m4 muscarinic cholinoceptors inhibits the cAMP-PKA pathway in corneal epithelial and endothelial cells resulting in decreased protein kinase A activity. Further work will be needed to clarify the physiological role of this signaling pathway in corneal epithelium and endothelium.

Mechanical behavior of nanocrystalline NaCl islands on Cu(111)

The mechanical response of ultrathin NaCl crystallites of nanometer dimensions upon manipulation with the tip of a scanning tunneling microscope (STM) is investigated, expanding STM manipulation to various nanostructuring modes of inorganic materials as cutting, moving, and cracking. In the light of theoretical calculations, our results reveal that atomic-scale NaCl islands can behave elastically and follow a classical Hooke's law. When the elastic limit of the nanocrystallites is reached, the STM tip induces atomic dislocations and consequently the regime of plastic deformation is entered. Our methodology is paving the way to understand the mechanical behavior and properties of other nanoscale materials.

Alcohol in the South Pacific: the mid-1990s

In the mid-1990s data were obtained on alcohol consumption in the Cook Islands, Fiji, Kiribati, Samoa, the Solomon Islands and Tonga. These data are reported together with a discussion of the nature of alcohol related problems in the island nations. Per capita consumption is highest in the Cook Islands, which compared with other countries has the highest ratio of liquor outlets and lowest alcohol taxation regime. As an alcohol problem prevention measure, it is concluded that the promotion of responsible consumption, together with the option of abstinence for those who wish it, is an acceptable strategy for the Pacific.

Medications for chronic pain practical review

This review is confined to the drug management of chronic pain, and is specifically adapted to the resource-poor environment and the HIV pandemic of sub-Saharan Africa. A brief classification of chronic pain is followed by a discussion of the different classes of medications in use, including those used in migraine. An approach to the rational drug management of neuropathic pain is presented. In conclusion some general principles for prescribing in this setting are derived.

[Effect of timolol on central corneal thickness and endothelial cell density]

BACKGROUND

The measurement of corneal thickness plays an increasing role in glaucoma screening and diagnosis. The influence of a variety of drugs on corneal thickness is well established. Especially for antiglaucomateous drugs this effect seems to be important. However, little is known about the influence of beta receptor antagonists on corneal thickness. The aim of this study was to provide evidence of the effect of timolol on central corneal thickness and endothelial cell density.

MATERIALS AND METHODS

Ten healthy volunteers (five women and five men) with a mean age of 29 years (range 25 to 56 years) were examined in a double-blind, prospective and randomised pilot study. Intraocular pressure, corneal thickness and endothelial cell density was estimated before as well as fifteen minutes, 24, 48, 72 and 96 hours after application of timolol 0.5 % eye drops twice daily. The partner eye received sodium hyaluronate eye drops twice daily and served as a control.

RESULTS

The application of timolol showed a decrease of intraocular pressure from initially 12 mmHg to 9 mmHg after four days (p = 0,0188) as well as an increase of corneal thickness from 537 microm to 557 microm after four days (p = 0,0659). There was no change of intraocular pressure (p = 0,9935) or corneal thickness (p = 0,9998) in the control eyes. There was also no effect of timolol (p = 0,2782) or sodium hyaluronate (p = 0,1940) on endothelial cell density.

CONCLUSIONS

The study provides evidence of the influence of beta receptor antagonists on corneal thickness. This effect may be caused by receptor mediated influences on corneal ion and fluid transport. Further studies are needed to show if the increase of corneal thickness after application of topical timolol has clinical importance.

[Protein kinase C isoforms in corneal epithelium and endothelium]

BACKGROUND

Protein kinase C (PKC) plays a key role in cell metabolism. Three subgroups and 12 isoforms have been isolated so far, catalysing specific functions in cell metabolism. The demonstration of PKC subtypes in corneal tissue has been inconsistent. The aim of this study was to verify the expression of several PKC subgroups and isoforms in human and bovine corneal epithelial and endothelial cells.

MATERIALS AND METHODS

PKC subgroups and isoforms were studied using polyclonal antibodies.

RESULTS

Antibodies to PKC-alpha, -delta, -epsilon and -zeta, representing all three PKC subgroups, bound in human and bovine corneal epithelium and endothelium. No binding was found for antibodies to PKC-beta2.

CONCLUSIONS

For the first time the presence of all three PKC subgroups was demonstrated in human and bovine corneal epithelial and endothelial cells. Further studies are needed to show the role of these subgroups in cellular functions such as cell proliferation and differentiation.

[Choroidal effusion syndrome after embolization of an indirect cavernous sinus fistula via the superior ophthalmic vein]

Embolization of a cavernous sinus fistula (SCF) via the superior ophthalmic vein (SOV) was reported to be an almost uncomplicated procedure, even after ligature of the vein at the end of the procedure. We report about a complication of this therapy. A 58-year-old female had a successful embolization of a right indirect cavernous sinus fistula via the SOV. At the end of the operation the SOV was ligated because of the danger of bleeding. Directly after surgery she experienced general worsening of the right eye with signs of venous congestion and marked effusion syndrome. The patient underwent total heparinization to achieve an opening of venous collaterals. Under local therapy with atropine 1% eye drops a decrease of the intraocular pressure was observed. The effusion syndrome was completely resolved within 1 month. If embolization of a cavernous sinus fistula is performed via the SOV, the ligature of the vein at the end of the procedure leads to thrombosis, which can reduce the venous stream from the eye and orbit. A secondary effusion syndrome with ocular hypertension because of a ciliolenticular block situation is possible and requires appropriate therapy. It is not possible to assess the capacity and time of opening of the venous collateral system before surgery. Therefore a transient outflow disturbance should be considered.

Epilepsy in sub-Saharan Africa: its socio-demography, aetiology, diagnosis and EEG characteristics in Harare, Zimbabwe

OBJECTIVE

To assess epileptics with regard to socio-demographic characteristics, aetiology, EEG results and classification.

DESIGN

A descriptive cohort study from 1997 to 2001.

SETTING

Parirenyatwa Group of Hospitals in Harare, Zimbabwe.

SUBJECTS

A total of 229 consecutive epileptic subjects.

RESULTS

The mean (s.d.) follow-up was 3.2 (1.14) years. The mean (s.d.) age of subjects was 23.4(11.8) years and 56% of them were males, over one third (43.1%) were unemployed and had secondary education (48%). Over one fourth (26.6%) of the subjects were first borns and had a family history of epilepsy (25.8%). Most of the subjects had Generalised Tonic Clonic Seizures (TCS). Over half (51.5%) of the subjects had their first onset of seizures after the age of 20 years. Lack of sleep (7.9%) and emotional disturbance (5.4%) were described by subjects as the frequent provoking factors for epileptic attacks. One hundred and fourteen subjects had electroencephalogram (EEG) results. Of these, 96 (41.9%) subjects had abnormal EEG results and only 18 (7.9%) had normal EEG results a majority (43.8%) of whom were of generalised slow waves. Majority of the subjects (52.8%) sought treatments from biomedical drugs, but some started with traditional herbs (20.5%) and then biomedical drugs, whereas others sought biomedical drugs then resorted to traditional herbs (20.1%). Phenobarbital and carbamazepine were taken by over 40% of the subjects.

CONCLUSION

The findings of this study seem to suggest that these referrals to a specialised epilepsy outpatient clinic for further management may be attributed to socio cultural issues in our African settings about the actual nature of the condition, hence the delay in treatments and diagnosis of seizures as well as under diagnoses of non-epileptic seizure disorders that may lead to the condition becomes uncontrollable. Inexpensive drugs such as phenobarbital and phenytoin can be able to control most of the epileptic seizures, if they can be made available in primary health care centres.

Keratoconjunctivitis epidemica

OBJECTIVE

The validity of the 15-min adenovirus assay SAS Adenotest was evaluated compared with virus detection by polymerase chain reaction (PCR) from conjunctival swabs.

METHODS

In 75 patients with assumed epidemic keratoconjunctivitis, adenovirus detection from conjunctival swabs was performed by the immunochromatographic assay SAS Adenotest and PCR.

RESULTS

In 25 patients adenovirus was detected by PCR, 18 of whom were detected by the SAS Adenotest and 7 of whom were not. No false positive results occurred. Sensitivity was 72% and specificity was 100%.

CONCLUSIONS

The results indicate that rapid adenovirus detection with the SAS Adenotest is a useful tool in early epidemic keratoconjunctivitis. An additional PCR should be performed when clinical symptoms persist for 5 days or more.

Breaking the silence: an HIV-related educational intervention for medical students in Zimbabwe

PROBLEM

A culture of silence surrounding HIV is a major contributor to continued HIV transmission and poor care for people living with HIV/AIDS.

AIM

To encourage medical leadership in addressing stigma and fear related to HIV at individual and community levels

OBJECTIVE

To pilot a mini-course for final year medical students in Zimbabwe that demonstrates stigma-reduction knowledge and skills needed to communicate information about HIV to patients, to address ethical implications of testing versus not testing for HIV, to increase awareness of the medical and preventive benefits of knowing one's HIV status and showing people how to cope with the emotional burden of dealing with HIV everyday.

DESIGN

Methods of proven effectiveness for training medical students in ethics and communication skills were used such as presentations by well respected role models and opinion leaders, role-playing, small group discussions, accompanied by materials indicating local resources, in three afternoon teaching sessions.

SETTING

University of Zimbabwe College of Medicine.

PARTICIPANTS

60 medical students, six lecturers, two facilitators and a group of actors.

MAIN OUTCOME MEASURES

Evaluation of the course by students showed appreciation of the course as measured on a scale of one to five for content and usefulness with requests for further inputs into the curriculum; model of mini-course that can be used by other medical schools in the southern Africa region and other areas of emerging HIV epidemics.

CONCLUSIONS

A brief educational intervention can help medical students to cope with the extraordinary challenge of providing care in high HIV prevalence countries and may contribute towards better leadership in addressing HIV epidemics.

Making research ethics review work in Zimbabwe--the case for investment in local capacity

OBJECTIVE

To describe the status of ethics review as pertaining to medical research in Zimbabwe, to compare this with international guidelines, and thus to identify potential improvements in the process.

DESIGN

The description includes background about the national review body, the Medical Research Council of Zimbabwe (MRCZ), and the findings of an analysis of institutional ethics review performed by the MRCZ liaison office.

RESULTS

Discrepancies with international guidelines include application of the concepts of independent and competent review, monitoring of ongoing studies, and ensuring appropriate membership of institutional ethics review committees (IRECs).

CONCLUSION

A focus on research ethics education for researchers and IREC members, as well as ensuring appropriate respect for IREC review, are opportunities for improvement in the process.

Kammerwasserdynamik

Intraocular pressure is mainly controlled by the rate of aqueous humor production and the resistance to its outflow. Aqueous humor formation is the result of fast unidirectional secretion and slow contradirectional reabsorption. The most striking evidence of endogenous regulation of the ciliary epithelial secretion is provided by the observation of the circadian rhythm. Aqueous humor formation is mainly controlled by the interaction of inhibiting alpha(2)-adrenoreceptors and stimulating beta-adrenoceptors. The role of the central nervous system in the regulation of this process remains unclear and the precise mechanism of outflow regulation is not fully understood. The aqueous humor passes into the anterior chamber and leaves the eye by two routes: the direct outflow pathway through the trabecular meshwork or the indirect outflow pathway through the ciliary muscle. Further biochemical, biological and pharmacological investigations are necessary to determine the fundamental process of aqueous humor formation, outflow and regulation.

Disability in an urban black community in Zimbabwe

PURPOSE

This study was undertaken to establish which health conditions are primarily responsible for disability and morbidity in a high-density area in Harare, Zimbabwe.

METHOD

House-to-house screening visits were followed up by medical examination and interview of those identified as having a functional limitation.

RESULTS

Information was obtained during screening on 10,839 residents. Of these, 608 were examined by medical professionals. The rate of disability/morbidity was 5.6% for the whole sample. Headaches and migraine were the most common problem. These were followed by back pain, hypertension and osteoarthritis. HIV/AIDS was the fifth most common condition. Depression, based on responses to a screening tool, was evident in one-third of the subjects. Common activity limitations included difficulty with the performance of housework activities and with walking. HIV/AIDS resulted in the most severe activity limitation, in that cognitive functions were also affected.

CONCLUSION

The middle-aged and elderly with osteoarthritis and young women with depression constitute vulnerable groups who are not in a position to demand services. The older women particularly need assistance as they are bearing the double burden of their own degenerative conditions and the results of the HIV/AIDS pandemic.

Auditory- and somatosensory-evoked potentials in cerebral malaria and anaesthesia: a comparison

BACKGROUND AND OBJECTIVE

Parallels exist between the coma associated with cerebral malaria and general anaesthesia. They both produce reversible loss of consciousness. In the case of cerebral malaria and in the absence of other complications, patients recover without sequelae. General anaesthetics are so designed that patients recover from their anaesthetics very quickly and show no 'after effects'. This study compares brain function in these two clinical conditions by examining auditory- (AEPs) and median nerve somatosensory-evoked potentials (SEPs). The AEPs studied (waves Pa and Nb) are thought to arise from the primary auditory cortex and the median nerve SEPs (waves P15, N20, P25, N35, P45) from the pons, thalamus and primary somatosensory cortices.

METHODS

Six comatosed patients with malaria (three males, three females) aged between 19 and 38 yr were studied in Zimbabwe. Their Glasgow Coma Scores on admission were 4, 3, 6, 7, 7 and 11. Their AEPs and median nerve SEPs were recorded daily over 4 days. The data were compared with those previously collected in the UK on patients and volunteers anaesthetized with desflurane, isoflurane, sevoflurane and propofol.

RESULTS

In general, patients with cerebral malaria showed AEPs and SEPs similar to those of light to moderate anaesthesia i.e. 0.5-1.25 measure of anaesthetic potency (MAC), where 1 MAC is the minimum alveolar concentration necessary to prevent movement to surgical incision in 50% of patients. The appearance of the AEPs and SEPs bore no relationship to the degree of coma. The auditory brainstem-evoked response was retained in all degrees of coma, as would be expected. Otherwise, it would not be possible to interpret the waveform. In most instances, the early cortical complex Pa/Nb/Pb of the AER was present. When comatose patients emerged from malarial coma or were stimulated by talking loudly to them, they showed changes in the Pa/Nb/Pb complex similar to those seen on awakening from anaesthesia. The somatosensory-evoked response showed clear P15, N20 and P25 peaks at the expected latencies, and in some instances the waveforms of cerebral malaria and lightly anaesthetized volunteers were very similar.

CONCLUSIONS

The sensory-evoked responses of the cerebral malaria patients recorded in this study were not markedly different from those seen in light-to-moderately anaesthetized patients and volunteers. The profound depression of the AEPs and SEPs associated with deeper levels of anaesthesia were not seen, with the exception of one patient several hours before death.

[Pseudohypopyon of cholesterol crystals occurring 16 years after retinal detachment in x-linked retinoschisis]

BACKGROUND

Cholesterol crystals of the anterior chamber can be found as a marked feature of advanced cholesterosis bulbi; typically following i. o. hemorrhage after severe trauma, retinal detachment or M. Coats.

CASE REPORT

A 39-year-old male patient with longstanding (16 years) retinal detachment in his right eye due to x-chromosomal linked retinoschisis presented with a clinical picture of a hypopyon and mature cataract. Ultrasonography showed a retrolental mass. Phacolytic uveitis was suspected and pars plana lentectomy and vitrectomy was performed. Intraoperatively subretinal chrystals could be detected. A specimen of the aqueous humor and subretinal fluid was evaluated biochemically and histologically and revealed cholesterol crystals.

CONCLUSIONS

Cholesterosis bulbi may be similar to lentogenic uveitis and should be included in the differential diagnosis of such processes. To our knowledge this is the first case of cholesterol crystals of the anterior chamber sixteen years after retinal detachment in x-linked retinoschisis.

[Bee sting of the cornea - a case report]

BACKGROUND

Bee stings of the cornea are very rare, though its response can range from minimal inflammation to severe damage like lens dislocation, cataract formation, iris atrophy, ophthalmoplegia and optic neuropathy. We report on a patient with typical, severe findings.

PATIENT

A 42-year-old patient presented with an acute, corneal bee sting of the left eye, after he was stung only a few hours ago. The patient suffered from pain, blurred vision and epiphora. The left eye showed edema of the upper and lower eyelid, conjunctival hyperemia, chemosis, striate keratitis, a purulent infiltration of the cornea above the limbus at the 7 o'clock meridian and a massive hypopyon. Further examinations showed regular ophthalmological findings. Vision acuity was 1,0/0,4. Under therapy inflammation decreased quickly. One week after we could lokalize the stinger in the depth of the corneal infiltration and it was removed surgically. After one month the eye only showed a minimal infiltration of the cornea with fine neovascularisations. Visual acuity was 0,8.

CONCLUSION

Clinical reactions to bee stings of the cornea are caused by toxical and immunological effects of different components of the bee venom. These toxical and/or inflammatory reactions can lead to severe intraocular damage. Treatment of choice is the systemic and local application of steroids and antibiotics as well as local therapy with antihistamins.

[Massive intraocular invasion of conjunctiva by squamous cell carcinoma--a case report]

BACKGROUND

Squamous cell carcinoma of the conjunctiva is a mostly solitary growing tumor located at the limbus region, which seldom invades the eye. We present an unusual case of conjunctival carcinoma with marked intraocular involvement, which appeared primarily as a chronic inflammation with corneal ulcer.

CASE REPORT

A 89-year-old female patient was referred to our institution with a suspected ulcus rodens of the cornea. Since one year a refractory conjunctivitis persisted despite of different local treatment. At first presentation, a marked bacterial keratoconjunctivitis with circular necrosis of the conjunctiva, corneal infiltration and perforation was seen. Visual acuity of the right eye was light perception. The left eye was unremarkable. Enucleation of the right eye was performed. Histopathologic examination revealed the diagnosis of squamous cell carcinoma of the conjunctiva with intraocular involvement. There was a marked infiltration of the choroid even behind the equator. No metastases were found.

CONCLUSION

Advanced squamous cell carcinoma associated with superinfection may present as a primary inflammatory process. There may be extensive involvement of the choroid. Metastases are probably rare even in advanced cases of this type of carcinoma.

Cryptococcus myelitis: atypical presentation of a common infection

Cryptococcus neoformans is associated with as much as 45% of meningitis in patients admitted for hospital care in Zimbabwe, and it is an important opportunistic infection in patients infected with the human immunodeficiency virus. Cases of cryptococcosis presenting as a spinal cord syndrome have been reported from Zimbabwe and South Africa, but these were all cases of Cryptococcus vertebral osteomyelitis. We describe 3 unusual patients who presented with a myelitis-like syndrome without vertebral osteomyelitis.

Community leader education to increase epilepsy attendance at clinics in Epworth, Zimbabwe

OBJECTIVE

To determine whether educating community leaders about epilepsy would lead to an increase in epilepsy cases being diagnosed and treated at primary health centers.

METHODS

This was a single-arm cohort study performed in Epworth, a periurban township outside Harare, Zimbabwe. The subjects were Epworth community leaders (Local Board members, teachers, nurses, police officers, traditional healers, prophets). Educational workshops were given on epilepsy, its cause, and its management, and the number of new epilepsy cases on local primary health clinic registers 6 months after the workshops was measured.

RESULTS

Six new cases were recorded, all among patients previously diagnosed with epilepsy. This was a significant increase (p = 0.02) compared with the null hypothesis.

CONCLUSION

Although there was a significant increase in new cases, these did not represent newly diagnosed patients. Significant prejudice within the community may still prevent identified patients with epilepsy from seeking treatment. Alternative methods must be sought to increase the awareness of epilepsy within low-income communities and to reach "hidden" people with epilepsy.

Impact of HIV infection on meningitis in Harare, Zimbabwe: a prospective study of 406 predominantly adult patients

OBJECTIVE

To determine the causative organisms and characteristics of patients presenting with features of meningitis.

DESIGN

A prospective cross-sectional study.

SETTING

Two tertiary university-affiliated hospitals in Harare, Zimbabwe.

PATIENTS

Four-hundred and six patients clinically suspected to have meningitis.

MAIN OUTCOME MEASURES

Causative organisms of meningitis; clinical and cerebrospinal fluid characteristics.

RESULTS

Four-hundred and six predominantly adult (95% were aged > or = 18 years) patients were suspected to have meningitis. Of the 200 patients confirmed to have meningitis, 89 (45%) had cryptococcal meningitis (CM), 54 (27%) had mononuclear meningitis (MM), 31 (16%) had pyogenic meningitis (PM), 24 (12%) had tuberculous meningitis (TBM) and 2 (1%) had undefined meningitis. HIV seropositivity was 100% in CM, 83% in MM, 81% in PM and 88% in TBM patients. In-hospital mortality rate was 38.8% for CM, 34.9% for MM, 68% for PM and 66.7% for TBM. HIV seropositivity was 80% in the 206 patients not found to have meningitis.

CONCLUSIONS

All patients suspected to have meningitis had a high HIV sero positivity irrespective of whether they were later confirmed to have meningitis or not. CM was the most common type of meningitis seen. In-hospital mortality was high irrespective of the cause of meningitis.

The impact of epilepsy on the quality of life of people with epilepsy in Zimbabwe: a pilot study

Epilepsy is a common cause of psychosocial disability and has been perceived to have a profound impact on the social functioning of individuals with epilepsy. In Zimbabwe a combination of developing world economic priorities (with provision of social and health services for disabled people not a major goal) and culturally mediated perceptions of epilepsy as a non-medical and feared stigma may further disadvantage people with epilepsy (PWE) in this respect. In order to assess both the level of psychosocial functioning of individuals with epilepsy and their own perception of it, three groups of people were sampled: attenders at a specialized epilepsy clinic and members of two community-based support groups. All completed a brief quality-of-life questionnaire with activities of daily living added. Those carers present completed the same questionnaire at the time of sampling. The results indicated that 36 of 38 people with epilepsy sampled, and their carers, did not perceive themselves to have sufficient cognitive impairment to interfere with social functioning, work performance or relationships with other as assessed by a subsection of the WHO SIDAM (objective evaluation of cognitive performance) interview. However, an adapted activities of daily Living Questionnaire (ADLQ) showed that three-quarters of carers (and two-thirds of PWE) felt that functioning was mildly to moderately reduced, particularly in the areas of solving daily problems and speed of thinking. One-quarter of PWE experienced problems with relationships to others, just less than one-fifth of PWE reported more than four areas of reduced functioning. Of special interest was the fact that 25 (66%) reported sexual functioning as not applicable, although only four of these were of an age group which is not sexually active (less than 15 years old). In addition one-third of the central Hospital Group reported difficulties with using public transport, but none of the Community Support Group members, implying that the use of Public transport becomes an issue when it is necessary to travel long distances and that PWE curtail their travel but do not necessarily view this as a restriction. The samples chosen were from groups which, compared with PWE as a whole, are likely to include more disabled individuals, because attenders at a specialized epilepsy clinic and members of support groups self-select for more symptomatic epilepsy and a visibility. Therefore the proportion of PWE perceived to have difficulties with ADL in this project is not representative for PWE as a whole. The implications of our study are firstly that there is a significant need for selected groups of PWE in Zimbabwe to receive attention to psychosocial abilities and secondly that there are certain specific areas such as sexual functioning and the use of transport which deserve special attention. A much more detailed inventory of neuro-psychological tests will be of value to plan treatment strategies for those selected by the crude screening instruments used in this project. An important future comparison will be a survey of ADL and psychosocial functioning amongst PWE in rural communities, because it is uncertain whether PWE in rural communities are generally more or less disabled than those in the city.

An evaluation of the management of epilepsy by primary health care nurses in Chitungwiza, Zimbabwe

In order to design an effective training program for nurses on the management of epilepsy in Zimbabwe, the drug management of epilepsy by community health nurses without prior training in epilepsy management was evaluated. Epilepsy patients in Chitungwiza, a high-density suburb of Harare, were routinely managed at four health clinics run by nurses. The patients also attended a monthly epilepsy support group (ESG) program, which provided them with vocational and social rehabilitative support. Neurologists evaluated the drug therapy of all patients attending this support group program over a 2-year period. The specialist interventions required to drug therapy in patients with inadequate seizure control or drug side effects were noted. A total of 114 epilepsy patients (age range 8-56 years, M:F=1:1.2) were seen, of these 84.2% had generalized seizures, 40.3% of patients had been seizure-free for at least 6 months, 71.9% of patients were on phenobarbitone, while 59.6% were on monotherapy. No drug intervention was required to on-going drug therapy in 43% of patient consultations. The most important intervention in patients with inadequate seizure control was an increase in drug dose, required in 29% of consultations. Of serum drug level estimations in clinically indicated cases, 58% were below the therapeutic ranges. This tendency to sub-therapeutic dosing with AED amongst nurses implied that a written AED drug therapy protocol specifying optimal maintenance doses and dose increment schedules may be beneficial to the community-based nursing management of epilepsy.

[Tübingen 1895-1899. Incidence, diagnosis and therapy of selected optic nerve, uveal and retinal diseases 100 years ago]

BACKGROUND

The records of the University Eye Clinic are almost completely preserved at the historical archive of the University of Tübingen since 1865 and shell now be reduced.

MATERIALS AND METHODS

150 records from the historical archive of the University of Tübingen were selected. We were interested in those patients treated for the first time at the University Eye Clinic between 1895 and 1899. Only diseases of the optic nerve, the uveal tract and the retina were considered. The records were distributed into groups following historical classification and statistics of the same period. These statistics were also used to compare our selection with all patients treated. For information about frequency, diagnostics and therapy a questionnaire was developed.

RESULTS

Glaucoma: The data of the subgroup "Glaucoma simplex" showed high correspondence with the historical data regarding the frequency (24.3 vs. 25.5%). The data of the subgroup "Glaucoma secundaria" differed (34.5 vs. 25.5%). Testing the visual acuity was the first step of examination here and in all groups (100%). Measurement of intraocular pressure with digital palpation followed (86.3%). First of all Eserin eye drops were applicated (76.5%). Iritis: The frequency of acute iritis was 16.8 vs. 25.0%, and of chronic iritis 59.6 vs. 52.2%. As typical symptoms ciliar injections, fixed anisocore pupil and exudation were often seen (80.0%). Chronic iritis showed as typical symptom posterior synechia (80.9%). Atropin eye drops were firstly applied in acute iritis (100%), chronical iritis was treated by iridectomy (57.1%). Myopia: In all subgroups our data differed from the historical data. Staphyloma posticum was the characteristic diagnosis (65.8%). Myopia was treated by decision of the lens. Retinal detachment: The frequency 37.2 vs. 28.0%. In nearly all cases retinal detachment was described after ophthalmoscopic examination (92.8%). The first therapeutical step was to keep the patients staying in bed (53.8%).

CONCLUSIONS

As expected, diagnostic and therapeutical options were strongly limited in Tübingen 100 years ago. Nevertheless, therapeutic successes were achieved in certain cases.

[Diode laser cyclophotocoagulation of secondary glaucoma caused by anterior, necrotizing scleritis]

PATIENT

A 60-year-old female patient presented with recurrent anterior, necrotizing scleritis with inflammation and a newly developed secondary glaucoma in the right eye. Anterior uveitis occurred some years before. Severe scleral thinning was circumferentially present and focal scleral ectasia was found. Physical examination revealed no systemic association of scleritis. Immunosuppressive therapy with metotrexate was initiated and control of scleritis achieved. Intraocular pressure elevation persisted and was refractory to glaucoma medication. Diurnal pressure curve showed IOP-values of 40 mm Hg despite the use of systemic carbonic anhydrase inhibitors. Visual acuity was 20/50 in the right and 20/25 in the left eye.

METHOD

Diode laser cyclophotocoagulation (Oculight SLx 810 nm, Iris Medical Instruments Inc. California, USA) was performed under general anaesthesia using reduced parameters for application (12 laser spots, 1 second, 1.25 W). No complications occurred during and after laser application. Postoperatively, intraocular pressure was within normal range between 14 and 18 mm Hg. No reactivation of scleritis or uveitis was seen.

CONCLUSION

In our experience, diode laser cyclophotocoagulation is effective and safe in treating secondary glaucoma associated with anterior, necrotizing scleritis with inflammation and uveitis using reduced parameters for application.