Effects of dextran on hippocampal brain slice water, extracellular space, calcium kinetics and histology

Hippocampal brain slices are valuable models for studying brain function but are compromised by several artifacts, including significant water gain and histologic injury, which occur under certain incubation conditions. Addition of colloid to Krebs-Ringer buffer (K-R) has been shown to eliminate water gain but has not achieved widespread acceptance. We confirm prior observations that dextran and PEG lessen the increase in slice mass during incubation in a dose-dependent manner with no water gain occurring at 4% concentrations. However, we also observe that addition of colloid to standard K-R induces severe neuronal pyknosis. Fortunately, the pyknosis can be eliminated by reduction in buffer osmolarity through adjustment of NaCl, producing markedly improved slice histology in dextran buffer, especially in the CA3 and CA4 regions of the hippocampus which are severely injured when incubated submerged in K-R at 37 degrees C. Extracellular space markers are not affected by either colloid. The volume of distribution for 45Ca is much larger in dextran buffers than in K-R and variability of 45Ca kinetics is also reduced. In the presence of dextran, hypoxia induces significant slice water gain, a relatively selective histologic injury and an alteration of tissue Ca2+ kinetics. Use of dextran buffers may eliminate many troubling brain slice artifacts.

Spontaneous extracranial carotid artery dissection in children

Dissection of cerebral arteries as a cause of stroke is rarely recognized in children. Two patients with stroke due to extracranial carotid artery dissection are reported. A 7-year-old girl with a 2-week history of right arm chorea had a left basal ganglia infarct and is receiving haloperidol for persistent chorea. The second patient, a 15-year-old boy, developed aphasia and right hemiparesis a day before admission during a football game without obvious trauma. He had a large left middle cerebral artery infarct and died of cerebral edema and herniation. We believe that strokes due to arterial dissection are more common than currently recognized, partly because of a lack of history of trauma, and suggest that cerebral artery dissection be considered as an etiology of childhood strokes. Greater awareness of arterial dissection as a cause of stroke and availability of noninvasive techniques like magnetic resonance angiography should result in a more accurate diagnosis and improved prognosis in these patients.

Effects of K+, pH and glutamate on 45Ca kinetics in hippocampal brain slices

Altered calcium homeostasis is likely to play a pathogenetic role in cerebral ischemia. In order to further understand which factors associated with ischemia contribute to disturbances of calcium metabolism, the influence of 3 isolated insults, 8 mM K+, pH 6.1 and 1 mM glutamate, on total tissue calcium were studied by analysis of steady-state kinetics of 45Ca in 500 microns hippocampal brain slices. 45Ca kinetics were analyzed with 2 bi-exponential models by non-linear least-squares analysis. Tissue wet weight/protein was measured simultaneously. Each experimental condition produced a unique tissue response. Raising K+ had no effect on tissue water but increased the rate of uptake of Ca2+ into the larger, rapidly equilibrating tissue Ca2+ space. Acidosis reduced tissue water and the amount of Ca2+ in the slowly equilibrating compartment due to enhanced efflux from that space. Glutamate increased tissue water in a time-dependent manner and increased the influx and amount of Ca2+ in the slowly equilibrating space. Combined insults revealed minimal interaction between K+ and acidosis or glutamate, but glutamate with acidosis worsened tissue injury. We discuss the relationship of this technique to other methods for studying tissue calcium and the significance of the observations regarding ischemia.

Special considerations in the endourologic management of stones in continent urinary reservoirs

To various degrees, all continent pouch designs are subject to stones, which often are infected. We report on the endourologic management of large stone burdens in three types of continent reservoirs. Stone in a UCLA and a Kock pouch were managed endoscopically, and stones in an augmented pouch with a Mitrofanoff valve were managed percutaneously. Recommendations are made with regard to the optimal endourologic management of significant stone burdens in each of the common continent urinary reservoirs.

Variability of intrinsic positive end-expiratory pressure in patients receiving mechanical ventilation

OBJECTIVE

Since variations in breathing pattern may affect the level of intrinsic positive end-expiratory pressure (PEEP), breath-to-breath variation of intrinsic PEEP was assessed.

DESIGN

Descriptive and prospective study.

SETTING

Medical intensive care unit of a university teaching hospital.

PATIENTS

Thirty-four patients requiring mechanical ventilation for a period of time due to respiratory failure.

MEASUREMENTS AND MAIN RESULTS

Intrinsic PEEP was determined using simultaneous recordings of the esophageal pressure and airflow. The breath-to-breath intrinsic PEEP, respiratory rate, tidal volume, inspiratory time, and fractional inspiratory time were measured. Intrinsic PEEP was noted in 33 of 34 patients. For all patients, the mean intrinsic PEEP was 3.59 cm H2O. The group mean standard deviation (SD) of the intrinsic PEEP over 35 breaths was 2.68 cm H2O. In 17 chronic obstructive pulmonary disease patients, the mean intrinsic PEEP was 4.69 cm H2O and the group mean SD of the intrinsic PEEP was 3.19 cm H2O. In the subgroup of patients with significant intrinsic PEEP, the mean intrinsic PEEP was 6.69 cm H2O and the group mean SD was 4.29 cm H2O. The group mean coefficient of variation of intrinsic PEEP for all 34 patients was 123%. Among the 15 patients with clinically significant intrinsic PEEP, the coefficient of variation was smaller (74%). We did not find significant correlation between the coefficients of variation of breathing pattern parameters and the coefficients of variation of intrinsic PEEP.

CONCLUSIONS

We conclude that the occurrence rate of intrinsic PEEP in mechanically ventilated patients is high. The degree of variability in intrinsic PEEP on a breath-to-breath basis is also high. It may be difficult to find a specific level of intrinsic PEEP. Addition of external positive end-expiratory pressure without considering the breath-to-breath variability may lead to overdistention of the lung.

Clinical correlation of periodic lateralized epileptiform discharges in children

Fifteen children with periodic lateralized epileptiform discharges are reported and clinical and radiologic features and outcome are presented. Both structural cerebral lesions and metabolic factors were associated with periodic lateralized epileptiform discharges. Although all patients had seizures, 8 had status epilepticus. Seven patients survived and 8 patients died. Six of the 7 survivors had residual seizures. Periodic lateralized epileptiform discharges in children are associated with acute encephalopathies and there is a high incidence of subsequent epilepsy.

Squamous cell carcinoma of the head and neck in the elderly

OBJECTIVE

While squamous cell carcinoma of the head and neck (HNSCC) most commonly affects individuals in the fifth to seventh decades of life, it occasionally arises in older patients. Biologic and epidemiologic factors of HNSCC in elderly patients have been investigated to shed light on the process of neoplastic transformation in that population.

DESIGN

The medical records of patients with new onset of HNSCC presenting between 1988 and 1993 were reviewed retrospectively.

SETTING

Tertiary-care hospital-based clinic.

PATIENTS

Eighty-one individuals who developed HNSCC of the upper aerodigestive tract after their 75th birthday constituted the study group. A control group consisting of 102 patients who developed HNSCC between the ages of 40 and 70 years was also analyzed.

MAIN OUTCOME MEASURE

Information about each individual's tobacco and ethanol exposure, family history of cancer, history of second primary cancer, treatment provided, and current disease status were derived from the medical record. The presence or absence of p53 gene mutation was tabulated for a subset of individuals in both the elderly and the middle-aged groups.

RESULTS

The elderly patients had a significantly lower degree of alcohol and tobacco exposure, but a significantly higher rate of second primary cancers, especially in sites outside the upper aerodigestive tract. There was no difference in the incidence of cancer in first-degree relatives in the two groups. These findings were interpreted in light of results from our laboratory examining the incidence of p53 gene mutation in a large number of patients with HNSCC. A significantly higher percentage of tumors from the younger group contained a p53 gene mutation. Major surgery was an integral part of the treatment plan for most of the older patient group despite their advanced age.

CONCLUSIONS

These findings suggest that HNSCC arising after the seventh decade of life less frequently involves a genetic change commonly found in younger patients. Heavy carcinogen exposure and p53 gene mutations are present less often in elderly individuals, whereas this group appears to be more susceptible to multiple cancers. The precise biologic factors involved in neoplastic transformation in this older population await discovery. Since aggressive therapy can be successfully tolerated by many elderly patients, an individualized approach to treatment is advocated.

Three-dimensional structure of the platelet integrin recognition segment of the fibrinogen gamma chain obtained by carrier protein-driven crystallization

We have developed a method for crystallizing small functional protein segments so that their three-dimensional structure can be determined by x-ray diffraction analysis. This method consists of linking a small protein segment of unknown tertiary structure to either the amino or carboxyl terminus of a larger carrier protein of known tertiary structure. Crystallization of the small segment is then driven by crystallization of the carrier protein. Using this approach, we have obtained crystals of the human fibrinogen gamma-chain carboxyl-terminal segment linked to the carboxyl terminus of chicken egg white lysozyme. The three-dimensional structure of the carboxyl-terminal segment of the fibrinogen gamma chain was determined by x-ray diffraction analysis at a resolution of 2.4 A. This segment encompasses the recognition site for the integrin alpha IIb beta 3 receptor on activated platelets and for the clumping receptor on pathogenic staphylococci and also bears donor and acceptor sites for factor XIIIa-catalyzed crosslinking of fibrin. Therefore, the structural information derived from our analysis will provide a rational basis for the design of inhibitors of these important functions of fibrinogen. Moreover, carrier protein-driven crystallization will facilitate the determination of the three-dimensional structure of functional segments of other proteins that are, like fibrinogen, difficult to crystallize in toto.

Effect of Ba 679 BR, a novel long-acting anticholinergic agent, on cholinergic neurotransmission in guinea pig and human airways

We investigated the effect of Ba 679 BR, a novel long-acting antimuscarinic agent, on cholinergic neural responses in guinea pig and human airways. Ba 679 BR, atropine, and ipratropium bromide inhibited electrical field stimulation (EFS)-induced contraction with IC50 values of 0.17, 0.74, and 0.58 nM, respectively, in guinea pig trachea. Ba 679 BR had a slower onset and longer duration of action than atropine or ipratropium bromide (the times required to attain 50% of the maximum response were 34.8, 3.8, and 7.6 min, respectively, and the times required for 50% recovery of the response were 540, 31.6, and 81.2 min, respectively). Ba 679 BR, as well as atropine and ipratropium bromide, facilitated evoked [3H]acetylcholine release (an inhibitory effect on prejunctional muscarinic M2 receptors). The facilitation of acetylcholine release by Ba 679 BR was lost 2 h after washout, however, when there was still complete blockade of cholinergic contractile responses evoked by EFS (an effect on airway smooth muscle M3 receptors), confirming binding studies that suggest that Ba 679 BR shows "kinetic receptor subtype selectivity" for M3 over M2 receptors. The high potency, slow onset, and long duration of action of Ba 679 BR were also observed in human bronchi, suggesting that Ba 679 BR may be a useful drug to provide convenient therapy for patients with obstructive airway disease.

Thrombosis of abdominal aortic aneurysms

The usual complication of abdominal aortic aneurysms is rupture. Although thrombosis of peripheral aneurysms is common, thrombosis of abdominal aortic aneurysms is rare. Sudden thrombosis of abdominal aortic aneurysms constitutes a surgical emergency, with a mortality of 50 percent. The patient often presents with cool and mottled skin, and with severe pain from the umbilicus to the lower extremities. Femoral pulses are rarely present, and neurologic deficits below the level of occlusion are common. We reviewed four recent patients with thrombosed abdominal aortic aneurysms. They presented with a range of symptoms that included impotence, abdominal pain, lower extremity pain, coolness, and weakness. Angiography in three of the patients revealed complete occlusion of the aorta. The fourth patient did not undergo angiography because of hemodynamic instability. Three of the four patients underwent thrombectomy, aneurysmectomy, and bypass grafting. The other patient underwent axillofemoral bypass grafting in lieu of aneurysmectomy because of severe coronary arteriosclerotic heart disease. All patients did well postoperatively. Our limited experience suggests that prompt diagnosis and surgical management of patients with thrombosed aortic aneurysms can lead to a successful outcome.

(Trifluoromethyl)lumazine derivatives as 19F NMR probes for lumazine protein

Lumazine protein acts as an electronic excited state transducer in bioluminescence of Photobacterium species. The protein binds 6,7-dimethyl-8-(D-ribityl)lumazine (1) which serves as the fluorophore. This compound also serves as a biosynthetic precursor of riboflavin and is the substrate of the enzyme riboflavin synthase. This enzyme and lumazine protein show considerable sequence homology. The interaction of lumazine apoprotein with several trifluoromethyl analogs of 6,7-dimethyl-8-ribityllumazine was investigated by 19F NMR spectroscopy. Upon binding to the protein, the 19F NMR resonances of the ligand shift to lower field with broadened line widths to around 30 Hz. By comparison, all ligands studied show more complex NMR spectra when bound to riboflavin synthase. Only one position 7 epimer (designated epimer A) of 6,7-bis(trifluoromethyl)-7-hydroxy-8-(D-ribityl)lumazine binds to lumazine apoprotein and riboflavin synthase. The apoprotein can also bind lumazine derivatives with a quarternary C-7. It is suggested that the binding site of lumazine protein corresponds to the donor binding site of riboflavin synthase.

Ligation of the T cell receptor complex results in activation of the Ras/Raf-1/MEK/MAPK cascade in human T lymphocytes

Stimulation of T cells with antibodies directed towards the T cell receptor complex results in the activation of mitogen-associated protein kinase (MAPK). Two pathways have been described in other cell types that can lead to MAPK activation. One of these pathways involves the activation of Ras, leading to the activation of Raf-1, and the subsequent activation of MEK (MAPK or ERK kinase). The contribution of this pathway in T cells for anti-CD3 or phorbol myristate acetate (PMA)-mediated MAPK activation was examined. We detected the kinase activities of Raf-1 and MEK towards their substrates (MEK for Raf-1 and MAPK for MEK) in this pathway leading to the activation of MAPK. Stimulation of the T cells with either anti-CD3 antibody or PMA resulted in a rapid activation of both Ras and Raf-1. MEK activity towards kinase-active or -inactive recombinant MAPK also increased upon stimulation. In addition, both MAPK and p90rsk were activated in these cells. We suggest that activation of MAPK and the subsequent activation of ribosomal S6 kinase (p90rsk) occurs by the Ras/Raf-1/MEK cascade in T lymphocytes stimulated by ligation of the T cell receptor complex.

Cross-linking of surface IgM stimulates the Ras/Raf-1/MEK/MAPK cascade in human B lymphocytes

The mechanism by which mitogen-activated protein kinase (MAPK) is activated in human B cells following cross-linking of the antigen receptor was investigated. Following anti-IgM antibody and phorbol 12-myristate 13-acetate (PMA) stimulation, we demonstrate the activation of Ras, Raf-1, and MAPK/ERK kinase (MEK), all of which are thought to participate in an important signaling cascade that leads to MAPK activation. We detected the kinase activities of Raf-1 and MEK toward purified recombinant substrates for each in this pathway (MEK for Raf-1 and MAPK for MEK). Following stimulation with either anti-IgM or PMA, Ras activation was observed, and the ability of Raf-1 to phosphorylate recombinant kinase-inactive MEK was increased by approximately 10-fold. Similarly, MEK activity toward kinase-active or -inactive recombinant MAPK also increased upon anti-IgM or PMA treatment. Furthermore, the activation of both MAPK and p90rsk was demonstrated under identical conditions in the B cells. We conclude that activation of B lymphocytes through the antigen receptor stimulates distinct members of the Ras/Raf-1/MEK cascade and this mechanism is likely to be responsible for MAPK and p90rsk activation in these cells.

Neurologic complications of pediatric liver transplantation

The neurologic complications of 24 children, ages 5 months to 18 years, following orthotopic liver transplantation at the Indiana University hospitals are reported. Biliary atresia (14 patients) was the most common cause for orthotopic liver transplantation. Three children died. Seventeen children (70%) had no neurologic deficit on follow-up 6 months or longer after transplantation. Eleven children (46%), including 4 of 16 patients (25%) who had received OKT3, had neurologic complications. Seven children (29%) had new-onset seizures; 4 of these patients had status epilepticus. Two children had intracranial hemorrhage. Seizures occurred later in children than in adults following orthotopic liver transplantation and were not associated with poor prognosis. Longer term follow-up is indicated to assess subtle, cognitive deficits following liver transplantation in children.

Fasting hyperglycemia in type I diabetes mellitus

The differential diagnosis of fasting hyperglycemia in type I diabetes includes the Somogyi effect, the dawn phenomenon, and insufficient insulin administration. To determine the causes of fasting hyperglycemia and their effect on subsequent daytime blood glucose control, the authors retrospectively reviewed blood glucose profiles of 126 patients with type I diabetes. The Somogyi effect accounted for 12.6% of all instances of fasting hyperglycemia, the dawn phenomenon, 24.1%, and poor control, 63.3%. Measurement of 3 AM and 5 AM blood glucose values is the key to making a correct diagnosis. Once a patient's fasting hyperglycemia is placed in one of these groups, appropriate treatment can be started.

MRI of Guillain-Barré syndrome

We describe the results of MRI of the spine in a case of Guillain-Barré syndrome. The main finding was abnormal enhancement of the nerve roots in the region of the conus medullaris and cauda equina.

Impact of treating involuntarily admitted schizophrenics on an open unit

When involuntary psychiatric patients are treated on unlocked units, problems may arise as to resource expenditure and the ability to provide optimal psychiatric care. This study investigates the problem and possible solutions.

Substance P inhibits the release of anterior pituitary adrenocorticotrophin via a central mechanism involving corticotrophin-releasing factor-containing neurons in the hypothalamic paraventricular nucleus

Chronic osmotic stimulation influences the hypothalamo-adenohypophysial axis by inhibiting the synthesis of hypothalamic corticotrophin-releasing factor (CRF-41) and subsequently the secretion of basal and adrenalectomy-elevated adrenocorticotrophin from the adenohypophysis. In the present study, we used a substance P antagonist to test the hypothesis that this inhibition is mediated centrally by substance P or other tachykinins. In control rats and rats given 2% saline to drink for 12 days, intracerebroventricular administration of a substance P antagonist elevated plasma adrenocorticotrophin and corticosterone levels. Using quantitative in situ hybridization histochemistry, it was also demonstrated that CRF mRNA increased in the medial parvocellular division of the paraventricular nucleus of saline-treated as well as control rats 6 h after intracerebroventricular administration of the antagonist, while vasopressin mRNA in the medial parvocellular division of the paraventricular nucleus was increased in the control animals only. These results provide evidence that central endogenous substance P has an inhibitory influence over the synthesis and release of CRF-41 both under normal conditions and during a chronic osmotic stimulus.

Aerocele, an unusual complication of anterior cricoid split

Since its introduction, the anterior cricoid split has proven to be a safe and effective procedure for the management of infants with acquired subglottic stenosis. In this article we report an unusual complication--an aerocele, which occurred on the 14th day following an anterior cricoid split on a 9-month-old child. The possible etiology and successful management of the aerocele are reviewed.

Structure of striated microtubule-associated fibers of flagellar roots. Comparison of native and reconstituted states

Several fiber systems are associated with the flagella and basal bodies of eukaryotic cells. Apart from the contractile and Ca(2+)-sensitive system-II fibers, these include the noncontractile system-I fibers that run parallel to flagellar root microtubules. Using electron microscopy and image reconstruction, we have investigated the structure of the system-I fibers of the flagellate green alga Spermatozopsis similis. The fibers were observed in three different states: (1) in situ, (2) after isolation of the intact fibers, (3) after disassembly and reconstitution of fibers in vitro from their 34 kDa subunit protein. The fibers are highly ordered; they show a constant repeat of 28 nm, they are polar, and they contain several transverse and longitudinal striations. A model is discussed showing the system-I fiber to be built from rod-like molecules with a staggered arrangement and identical polarities.

Comparison of Sentinel and Bactec blood culture systems

AIMS

To evaluate the Sentinel automated blood culture system and to compare its performance with that of Bactec.

METHODS

The Sentinel blood culture system was evaluated in three centres. The performance of the system was assessed in comparison with the routine blood culture method used in these centres, the Bactec system.

RESULTS

Blood culture sets (n = 2180) consisting of Sentinel aerobic and anaerobic, and Bactec aerobic and anaerobic bottles yielded 218 (10%) clinically important isolates. One hundred and fifty five (71%) of the isolates were detected by both systems; 35 (16%) were detected by Sentinel only; and 28 (13%) by Bactec only. For the duration of the evaluation, the Sentinel system was deliberately configured so that it was impossible to detect positive results during the first 12 hours. The times to positivity after the first 12 hours were similar. Data gathered during and subsequent to the evaluation have been used by the manufacturer to refine the algorithm so that positive results can be detected at a minimum of 2.25 hours.

CONCLUSIONS

After a period of familiarization the Sentinel system was considered easy to use. Sentinel is a useful addition to the methods available for the detection of bacteria in blood cultures.

Eicosatetraynoic and arachidonic acid-induced changes in cell membrane fluidity consonant with differences in computer-aided design-structures

ETYA (5,8,11,14-eicosatetraynoic acid), a competitive analogue of arachidonic acid (AA), inhibits the proliferation of U937 (human monoblastoid) and PC3 (human prostate) cancer cells, without the overt cytotoxicity associated with AA at similar concentrations. The mechanism of inhibition is not established. ETYA at 100 microM acutely increased whole cell and isolated microsomal membrane fluidity of both cell lines to a greater extent than arachidonic acid. PC3 cells incubated with ETYA for 72 h evidenced increased membrane fluidity. This was measured by the fluorescence polarization parameter, R, using the probes TMA-DPH and DPH for whole cell and isolated membrane fractions, respectively. Compared with whole cells, isolated membranes yielded a 10-20-fold increase in fluorescence intensity. The intramolecular conformational profiles of both ETYA and AA were explored using a combination of molecular mechanics energy minimization and molecular dynamics simulation. While it is possible that not all of the low energy conformational states of either molecule were sampled, the large number of low-energy conformers determined for ETYA correspond to kink deformed conformers relative to the family of AA conformers. These kinks make the molecular cross sections of ETYA larger than AA and arise from the four alkyne bond geometries. This structural finding is consistent with ETYA's greater effect on membrane fluidity. Dissociation between the extent of change in membrane fluidity due to ETYA or AA and inhibition of DNA synthesis can suggest that either (A) increased fluidity and inhibition of DNA synthesis are independent, or as we believe more likely, (B) greater membrane fluidity evoked by ETYA is important for inhibiting DNA synthesis, while changes induced by AA are insufficient or differ qualitatively from those required to initiate and sustain these nonlethal events.

Prostate Specific Antigen Levels After Radical Prostatectomy in Patients with Organ Confined and Locally Extensive Prostate Cancer

A total of 230 patients with localized prostate cancer underwent radical retropubic prostatectomy at UCLA (pathological stage T1-3 N0, M0). Classification into groups included 115 patients with organ confined disease (group 1), 82 with invasion into or through the capsule (group 2) and 33 with seminal vesicle involvement (group 3). Median followup was 48 months. The 10-year, cause-specific survival was 96%, 90% and 63%, and 5-year, clinical, disease-free survival was 91%, 79% and 58% for the 3 groups, respectively. Recent prostate specific antigen (PSA) levels were measured in most patients, even those operated upon many years ago. Of the patients 41 had detectable (0.4 ng./ml. or greater) PSA levels without any other clinical evidence of progression and 15 with clinical evidence of progression had PSA levels in the detectable range at the time of clinical progression. When isolated detectable PSA was also considered an indicator of progression the 5-year and 10-year, disease-free rates were 61% and 41%, respectively. These data show that radical prostatectomy performed in patients with even microscopic invasion into the capsule, positive margins and seminal vesicle involvement is associated with a higher clinical progression rate than organ confined disease. If isolated detectable PSA is also considered an indicator of recurrence the disease-free survival after radical prostatectomy might be less than indicated by previous studies. The relationship among survival, local tumor extension and PSA must be carefully examined.

Altered adrenocorticotropin, corticosterone and oxytocin responses to stress during chronic salt load

We have investigated the effects of stress on the plasma levels of adrenocorticotropin (ACTH), corticosterone and oxytocin (OT) in rats given 2% saline to drink for 12 days. Plasma ACTH levels were markedly decreased from 972 +/- 165 pg/ml in the control animals on water to 349 +/- 114 pg/ml in animals given 2% saline to drink. Stress-induced release of ACTH observed in animals on water (controls = 972 +/- 165 pg/ml and stressed animals = 1,439 +/- 105 pg/ml) was completely abolished following 2% saline treatment for 12 days (controls = 349 +/- 114 pg/ml and stressed animals = 205 +/- 27 pg/ml). After 2% saline, plasma corticosterone levels were unaltered in control and stressed animals as compared to control animals on water in which stress increased plasma corticosterone from 28.8 +/- 7.9 to 99.5 +/- 8 ng/ml. In contrast to ACTH, the OT response to stress was intact in animals on 2% saline despite raised plasma OT in the control group due to the osmotic stimulus. Removal of the source of circulating glucocorticoids by adrenalectomy partially restored both basal levels of ACTH and the response to stress in animals on 2% saline. Our results demonstrate that 2% saline treatment activates an inhibitory mechanism over the release of ACTH.

Lanosterol 14 alpha-demethylase (P45014DM): effects of P45014DM inhibitors on sterol biosynthesis downstream of lanosterol

Lanosterol 14 alpha-demethylase (P45014DM) is the cytochrome P450 enzyme complex responsible for an early step in cholesterol biosynthesis, namely the 14 alpha-demethylation of lanosterol. We have synthesized a novel series of steroidal substrate analogues, designed to be specific and potent inhibitors of P45014DM. We describe here the effects of these compounds on sterol biosynthesis downstream from lanosterol, focusing ultimately on their efficacy as inhibitors of cholesterol biosynthesis. Results using a radio-high performance liquid chromatography (HPLC) assay show that in rat liver microsomal preparations, with [24,25-3H]dihydrolanosterol as substrate, the compounds do indeed inhibit the biosynthesis of sterols downstream from lanosterol. A range of inhibitory potencies was observed, and the key enzyme being inhibited was believed to be P45014DM. Inhibitor efficacy was readily correlated with non-metabolized [24,25-3H]dihydrolanosterol, formation of 4,4-dimethyl-cholest-8-en-3 beta-ol, and formation of lathosterol, a sterol believed to be an excellent indicator of whole body cholesterol biosynthesis in humans.

The interaction of boar sperm proacrosin with its natural substrate, the zona pellucida, and with polysulfated polysaccharides

Boar sperm acrosin is an acrosomal protease with trypsin-like specificity, and it functions in fertilization by assisting sperm passage through the zona pellucida by limited hydrolysis of this extracellular matrix. In addition to a proteolytic active site domain, acrosin binds the zona pellucida at a separate binding domain that is lost during proacrosin autolysis. In this study, we quantitate the binding of proacrosin to the physiological substrate for acrosin, the zona pellucida, and to a non-substrate, the polysulfated polysaccharide fucoidan. Binding was analogous to sea urchin sperm bindin that binds egg jelly fucan and the vitelline envelope of sea urchin eggs. Proacrosin was found to bind to fucoidan and to the zona pellucida with binding affinities similar to bindin interaction with egg jelly fucan. These interactions were competitively inhibited by similar relative molecular mass polysulfated polymers. Since bindin and proacrosin have distinctly different amino acid sequences, their interaction with acidic sulfate esters demonstrates an example of convergent evolution wherein different macromolecules localized in analogous sperm compartments have the same biological function. From cDNA sequence analysis of proacrosin, this binding may be mediated through a consensus sequence for binding sulfated glycoconjugates. Proacrosin binding to the zona pellucida may serve as both a recognition or primary sperm receptor, as well as maintaining the sperm on the zona pellucida once the acrosome reaction has occurred.

Rapid culture confirmation of herpes simplex virus by a monoclonal antibody-based enzyme immunoassay

Rapid confirmation of herpes simplex virus (HSV) is essential in many clinical settings. Viral isolation in cell culture is the standard method for diagnosing HSV infection, with confirmation by specific immunological staining. The performance of the Rapid Absorbent Matrix Pad (RAMP) HSV culture confirmation test was evaluated with specimens obtained from 71 patients with suspected HSV infection and inoculated into African green monkey kidney cell lines. Forty-one culture-positive specimens were confirmed to be HSV by both the RAMP HSV test and the Bartels HSV immunoperoxidase test. Thirty immunoperoxidase-negative specimens were also negative in the RAMP HSV test. The sensitivity and specificity of the RAMP HSV test were 100%. Twelve specimens positive for cytomegalovirus, adenovirus, or enterovirus tested negative by the RAMP HSV test. Thus, the RAMP HSV test was faster than, easier to perform than, as sensitive as, and as specific as other well-documented confirmation methods.

Lactation abolishes corticotropin-releasing factor-induced oxytocin secretion in the conscious rat

We have assessed the response of plasma oxytocin (OT) to intracerebroventricular CRF-41 in both virgin female and lactating rats. In virgin rats CRF-41 resulted in an increase in plasma OT from 5-30 min after administration. In lactating rats, however, there was a complete abolition of the OT response, even at the highest dose of CRF-41. These data demonstrate another feature of the hormone nonresponsiveness apparent during lactation and suggests that one of the reasons for the lack of stress responses could be a down-regulation of the response to endogenously released CRF-41.

Gas chromatography of C19 and 17-oxogenic steroids in urine

17-oxogenic steroids have been analysed by gas chromatography (GC) with capillary column and flame ionization detector. The best separation of steroid products was gained after ethyloxime-trimethylsilyl ether formation. The value of the GC method as a screening procedure for patients with suspected adrenal disease is illustrated in selected cases where the diagnosis was equivocal from data derived by RIA analysis of plasma steroids.

Polydipsia and hyponatremia induced by multiple neuroleptics but not molindone

A 37 year old patient with chronic schizophrenia developed polydipsia and hyponatremia induced by several neuroleptics. We treated the patient successfully with molindone. The etiology of polydipsia with hyponatremia is discussed.

The effects of chronic obstructive airways disease on the ability to drive and to use a roadside alcolmeter

Subjects with chronic obstructive airways disease may have difficulty with the roadside alcolmeter. Twenty-six subjects with a FEV1/FVC less than 60% were asked to use an alcolmeter simulator. Only ten were able to produce the necessary flow rate of 28 l min-1 for a minimum of 2.7 s, two could produce the same total volume (1.25 l) at 10 l min-1 for 7.5 s, five could only expel 10 l min-1 for 4.5 s, and nine were unable to trigger the alcolmeter at even these very low flow rates. Subjects with an FEV1 of less than 1.51 or FEV1% predicted less than 50% were very unlikely to be able to activate the alcolmeter. Ten healthy subjects were investigated to assess the accuracy of the roadside alcolmeter at a flow rate of 10 l min-1 compared to 40 l min-1. No significant difference was found in breath alcohol levels between the two flow rates. It is proposed that some modification could be made to the roadside alcolmeter, without affecting its accuracy, to allow some subjects with chronic obstructive lung disease to activate the device. A postal survey of 284 subjects with a FEV1/FVC less than 60% was carried out. Of those who were drivers or exdrivers, 24.7% had had to stop or reduce their driving because of their respiratory disease. This group had a significantly lower FEV1% predicted (P = 0.035) than those whose driving was unaffected.

Idiopathic unilateral hyperlucent lung

The entity of unilateral hyperlucent lung in the adult is presented as a disease which has its origins in childhood and carries the potential for cardiopulmonary morbidity.

History of separation anxiety in patients with panic disorder and depression and normal controls

The frequency and severity of separation anxiety for subjects with panic disorder and major depression was compared with that for normal controls. The subjects were diagnosed according to DSM-III criteria. Each subject completed a questionnaire consisting of 9 items derived from DSM-III criteria for separation anxiety disorder. The incidence of separation anxiety and its severity were significantly higher for the panic disorder subjects than for normal controls but there was no significant difference between depressed and panic disorder subjects. Panic disorder subjects with a history of separation anxiety disorder had a significantly earlier onset of panic attacks.

Use of lacZ expression to monitor transcription

For use in monitoring transcription in operon fusion, we have constructed a lacZ sequence with the initiation codon ATG and the Escherichia coli consensus Shine-Dalgarno site. There are unique restriction endonuclease sites flanking the sequence to allow easy isolation of the lacZ sequence with or without the Shine-Dalgarno site. We have placed this lacZ sequence behind the bovine growth hormone (BGH) gene and found that the lacZ product beta-galactosidase synthesized reflects the level of BGH-specific mRNA.

Sources of error in neonatal blood sampling

Significant underestimation of blood electrolyte concentrations may occur if less than 1 ml of blood is withdrawn from an indwelling arterial line before taking the sample for analysis. Compared with arterial samples capillary samples give significant overestimations of potassium concentration and carbon dioxide tension, and significant underestimation of oxygen tension.

Acute staphylococcal septic arthritis: the effect of cloxacillin therapy in an avian model

An experimental model of acute staphylococcal septic arthritis in chickens was used to study the effect of different therapeutic regimens of the antibiotic cloxacillin on the natural history of the disease. Three different therapeutic regimens were used in order to assess the effect of increasing the frequency and of delaying the commencement of administration. The results were assessed by measurement of animal growth rate, clinical condition, bacterial and leukocyte counts in synovial fluid, and histological appearance. An inadequate dosage regimen (a single daily dose) prevented spread of bacteria but did not control abscesses. Delay in commencing treatment permitted persistence and spread of abscesses with destruction of the secondary (epiphyseal) ossification center and even transphyseal spread into metaphyseal bone. Repair by fibroblasts was mainly seen in articular and epiphyseal cartilage but was not seen in the epiphyseal ossification center during the duration of the experiments (up to 18 days). Synovial fluid sampling with measurement of leukocyte and bacterial concentrations appears to be a useful guide to the effectiveness of treatment, because the numbers of cells correlate with the pathological process.

Temporal relationships in the effects of protein-free diet on the activities of rat liver branched-chain ketoacid dehydrogenase complex and kinase

Feeding rats 0% casein diet decreased liver activities of branched-chain ketoacid dehydrogenase complex (active form) and of activator protein (complete within 4 days), and increased activity of branched-chain ketoacid dehydrogenase kinase (complete within 9-10 days). Refeeding normal diet to rats fed 0% casein diet for 10 days resulted in a rapid and partial (approx. 50%) reversal of the above effects within 24 h; complete reversal required 20-30 days of refeeding.

Induction of a cationic shift in IgG anti-DNA autoantibodies. Role of T helper cells with classical and novel phenotypes in three murine models of lupus nephritis

We investigated the underlying mechanisms of systemic autoimmune disease in MRL-+/+, (NZB X NZW)F1, and (NZB X SWR)F1 mice, since these strains develop glomerulonephritis without the superimposition of any secondary lupus-accelerating genes. All three strains manifested a common immunoregulatory defect specific for the production of pathogenic anti-DNA autoantibodies that are of IgG class and cationic in charge. At or just before the age they began to develop lupus nephritis, spleen cells of the mice contained a subpopulation of Th cells that selectively induced their B cells in vitro to produce highly cationic IgG autoantibodies to both single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). By contrast, T cells from younger preautoimmune mice were incapable of providing this help. Moreover, only B cells of the older lupus mice could be induced to secrete cationic anti-DNA antibodies of IgG class. B cells of young lupus mice could not produce the cationic autoantibodies even with the help of T cells from the older mice, nor upon stimulation with mitogens. In the older lupus mice we found two sets of Th cells that spontaneously induced the cationic shift in autoantibodies; one set belonged to the classical Th category with L3T4+,Lyt-2- phenotype, whereas the other surprisingly belonged to a double-negative (L3T4-,Lyt-2-), Lyt-1+ subpopulation. The latter set of unusual Th cells were unexpected in these lupus mice since they lacked the lpr (lympho-proliferation) gene. Thus three apparently different murine models of systemic lupus erythematosus possess a common underlying mechanism specific for the spontaneous production of pathogenic anti-DNA autoantibodies.