Lisch corneal dystrophy is genetically distinct from Meesmann corneal dystrophy and maps to xp22.3

PURPOSE

There is an ongoing discussion whether Lisch corneal dystrophy (band-shaped and whorled microcystic dystrophy of the corneal epithelium) represents a disorder that is different from Meesmann corneal dystrophy. The purpose of this study was to evaluate at the molecular level if Lisch and Meesmann corneal dystrophies are genetically distinct.

METHODS

We examined at the slit lamp a total of 48 members of a family with an aggregation of Lisch corneal dystrophy. Genomic DNA was extracted from leukocytes of the peripheral blood of seven affected and six unaffected members of this family. Mutational hotspots in the cornea-specific keratin genes K3 and K12 were scanned for mutations by single-strand conformation analysis. To test for linkage to the keratin K3 or K12 loci or for X-chromosomal inheritance, six (K3) and four (K12) microsatellite markers each flanking the keratin loci as well as 22 microsatellite markers covering the X-chromosome were typed. Linkage was analyzed using the MLINK and FASTMAP procedures.

RESULTS

A total of 19 trait carriers were identified in six generations of the family. No hereditary transmission from father to son was observed. Linkage was excluded for the keratin K3 and K12 genes. Furthermore, single-strand conformation analysis detected no mutations in these genes. Multipoint linkage analysis revealed linkage with a maximum likelihood of the odds (LOD) score of 2.93 at Xp22.3. Linkage was excluded for Xp22.2 to Xqter.

CONCLUSIONS

Lisch corneal dystrophy is genetically different from Meesmann corneal dystrophy. Evidence was found for linkage of the gene for Lisch corneal dystrophy to Xp22.3.

Determination of time-dependent skin temperature decrease rates in the case of abrupt changes of environmental temperature

The present study deals with the development of a method for determining time-dependent temperature decrease rates and its application to postmortem surface cooling. The study concentrates on evaluating skin cooling behavior since data on skin cooling in the forensic literature are scarce. Furthermore, all heat transfer mechanisms strongly depend on the temperature gradient between body surface and environment. One of the main problems in modelling postmortem cooling processes is the dependence on the environmental temperature. All models for postmortem rectal cooling essentially presuppose a constant environmental temperature. In medico-legal practice, the temperature of the surrounding of a corpse mostly varies; therefore, an approach for extending the models to variable environmental temperatures is desirable. It consists in 'localizing' them to infinitesimal small intervals of time. An extended model differential equation is obtained and solved explicitly. The approach developed is applied to the single-exponential Newtonian model of surface cooling producing the following differential equation:T(S)'(t)=-lambda(t)(T(S)(t)-T(E)(t))(with T(S)(t) the surface/skin temperature, T(E)(t) the environmental temperature, lambda(t) the temperature decrease rate and T(S)'(t) the actual change of skin temperature or first-order derivative of T(S)). The differential equation directly provides an estimator:lambda(t)=-T(S)'(t)T(S)(t)-T(E)(t)for the time-dependent temperature decrease rate. The estimator is applied to two skin cooling experiments with different types of abrupt changes of environmental temperature, peak-like and step-like; the values of the time-dependent temperature decrease rate function were calculated. By reinserting them, the measured surface temperature curve could be accurately reconstructed, indicating that the extended model is well suited for describing surface cooling in the case of abrupt changes of environmental temperature.

The neuropathology of heroin abuse

A broad spectrum of neuropathologic changes are encountered in the brains of heroin abusers. The main findings are due to infections, either due to bacterial spread from bacterial endocarditis, mycoses, or from HIV-1 infection. Other complications include hypoxic-ischemic changes with cerebral edema, ischemic neuronal damage and neuronal loss, which are assumed to occur under conditions of prolonged heroin-induced respiratory depression, stroke due to, for example, thromboembolism, vasculitis, septic emboli, hypotension, and positional vascular compression. Myelopathy is believed to be the result of an isolated vascular accident within the spinal cord due to an as yet unknown mechanism. A distinct entity, spongiform leukoencephalopathy, has been described mainly after inhalation of pre-heated heroin. A lipophilic toxin-induced process was considered to be due to contaminants and to be induced or enhanced by cerebral hypoxia, but a definite toxin could not be identified. At the cellular level, abnormalities in signal transduction systems and changes of various receptor densities have been reported. The exact etiology of the different neuropathological alterations associated with heroin abuse is still unclear, but may also be related to additional substances used as adulterants.

[The driving simulation test "carsim" for assessing vigilance. Effect of driving practice and other factors in health subjects and in patients with sleep apnea syndrome]

Among other factors, obstructive sleep apnoea (OSAS) patients suffer from impaired continuous attention. For registration and objectification as well as observation of the course of therapy, driving simulation programmes are particularly suitable. "Carsim", a driving simulation newly developed by us, simulates a bendy road via a screen where a vehicle is supposed to be kept on the right lane by operating a steering wheel. Apart from examination of quality criteria (objectivity, reliability, validity) and establishment of standard values, the influence of significant variables (age, gender, school education, profession, duration of disorder, AHI, BMI, visual and motor functionability, driving license, driving experience, Epworth score, accident frequency) on patients and healthy controls requires to be evaluated. For this purpose, 100 healthy controls, 200 OSAS patients and 30 patients under nCPAP were analysed. In healthy persons and patients under nCPAP, driving experience had no impact on the driving simulation results. OSAS patients with no driving license and no driving experience achieved lower marks for tracking than patients with driving license or a lot of driving experience (no driving license: x = 8058 +/- 10,878 track deviations; with driving licence: x = 2111 +/- 6564 track deviations; p < .001). According to our findings, untreated OSAS severely interferes with patients' attention capacity as well as their coping strategies.

Histologically repeatedly confirmed gliosarcoma with long survival: review of the literature and report of a case

OBJECTIVE AND IMPORTANCE

A rare case of gliosarcoma in a 61-year-old woman is presented with a stable situation over 22 years with an excellent quality of life.

CLINICAL PRESENTATION

The patient was initially symptomatic and was operated on in 1975 for a deep-seated left parietal gliosarcoma. During the following 20 years, she was clinically asymptomatic until she complained of increasing headache in 1995. Neuroradiological imaging showed a sharply demarcated lesion on MRI at the former operative site, which was operated on again. Four months later, the residual tumour did grow again.

INTERVENTION

As radiation therapy could not stop tumour progression and the neurological status worsened, the patient was operated on again for a massive tumour mass in the left parieto-occipital region, filling out nearly all of the previous resection cavity. Despite radio-immunotherapy, the patient finally died 22 years after the first discovery of the tumour.

CONCLUSION

The present case shows that, in rare instances, gliosarcomas may show prolonged survival, although the underlying pathogenetic mechanisms for this clinical behaviour are not understood.

Lipoma of the adrenal gland

A rare case of a lipoma of the adrenal gland is reported with a review of the literature. The tumor was incidentally found at autopsy in a 50-year-old man who died from severe head trauma after a traffic injury. At autopsy, an oval-shaped, soft yellow nodule measuring 1.1 cm in diameter was found in the right adrenal cortex. Histological examination revealed a lesion consisting of mature adipose tissue partially surrounded by a thin fibrous capsule. On serial sections there was no evidence of hematopoiesis nor of adrenal medulla cells. To the best of our knowledge, this is the eighth case described in the English literature. With the increasing use and the high resolution of modern imaging techniques, these unsuspected adrenal masses may become more prevalent.

Energy loss due to radiation in postmortem cooling. Part B: Energy balance with respect to radiation

With the help of the law of Stefan and Boltzmann and a model for the cooling of exposed skin derived from the data of Lyle and Cleveland, the radiation energy loss ER can be calculated according to the following formula: [formula in text] where epsilon represents the emissivity of the skin (0.98), sigma the Stefan-Boltzmann constant, AR the radiating surface area, TS(0) the skin temperature at death, TE the environmental temperature and Z' = 0.1017 the gradient of the skin temperature curve. Additionally, an energy loss due to conduction and convection EC has to be taken into account. Comparing the energy losses due to radiation, conduction and convection with the decrease ET of the thermal energy in the body, calculated from mean heat capacity (3.45 kJ/(kg degrees K)), body mass and decrease of mean body temperature, there is a surplus of energy in the very early postmortem period, which can be explained only by an internal source of energy EI. Alltogether the following balance equation can be formulated: ET + EI = ER + EC Since the body temperature decreases in the early postmortem period, EI can be estimated by: EI(t) > or = max (ER(t) - ET(t), 0). The values obtained range up to 500 kJ for a medium sized (175 cm), medium weight (75 kg) body at an environmental temperature of 5 degrees C and are compatible with estimations of Lundquist for supravital energy production by breakdown of glycogen.

Sudden natural death 'at the wheel': a retrospective study over a 15-year time period (1982-1996)

In order to investigate the incidence and implications of sudden natural death at the wheel, a retrospective study was carried out over a 15-year time period ranging from 1982 until 1996. During this time period 147 drivers of motor vehicles were found out of 34,554 cases examined at the Institute of Legal Medicine, Ludwig-Maximilians University, Munich, Germany. There were 13 females and 134 males and the mean age was 56.8 years (range 20-86 years). The main cause of death was ischemic heart disease which was found in 113 cases. There were mainly minor injuries to the driver, or to other passengers, or to other road users and only minor property damage. Our study confirms previous investigations that sudden natural death at the wheel is a rare event in proportion to unnatural death at the wheel and is not a substantial threat to other road users. Despite existing guidelines for granting a driving licence, medical screening to exclude high risk patients from driving cannot prevent the occurrence of sudden natural death at the wheel.

Rare occurrence of intracerebellar colloid cyst. Case report

Colloid cysts are rare intracerebral lesions that are preferentially encountered within the third ventricle. There are only a few reports in which colloid cysts are described in other locations such as the fourth ventricle. A symptomatic intracerebellar colloid cyst in a 45-year-old woman is described. The patient presented with headache, gait disturbance, and nausea. Neuroradiological imaging revealed compression of the fourth ventricle, hydrocephalus, and an intracerebellar cystic lesion measuring 4 x 5 cm that had a small peripheral solid portion. The cyst was successfully removed via a paramedian suboccipital approach. Postoperatively, the patient recovered quickly. The findings in the present report represent an additional example of the broad spectrum of cystic lesions encountered in the cerebellum.

Unexpected death in persons with symptomatic epilepsy due to glial brain tumors: a report of two cases and review of the literature

Two cases of unexpected death in persons with epileptic seizures due to a brain tumor are presented which encompassed an astrocytoma WHO grade II and an anaplastic astrocytoma WHO grade III. A 35-year-old man was found somnolent and disoriented at home. A computed tomography (CT) scan revealed a tumor of the right frontal lobe suggestive for an oligodendroglioma. During an angiographic examination the patient experienced an epileptic seizure. Some weeks later, the man was found dead in front of his house with a fresh bite mark of the tongue. Neuropathological examination revealed an astrocytoma WHO grade II of the right frontal lobe. A 47-year-old man plunged into a swimming-pool and was found submerged some minutes later. After resuscitation he survived comatose for 8 days but finally died due to severe hypoxic brain damage. He had been operated on a brain tumor of the temporal lobe 1 year before the accident. Neuropathological examination revealed residual tumor tissue at the operation site corresponding to an anaplastic astrocytoma WHO grade III. Although rare, death in persons with epileptic seizures due to brain tumors is an important mechanism of death encountered by the forensic pathologist.

Non-lymphomatous brain tumors in HIV-1 infection: a review

A broad spectrum of malignant tumors affecting various organ systems in HIV-1 infected patients have been described in larger series. Intracerebral mass lesions encountered in HIV-1 infection are mostly due to toxoplasmosis and central nervous system (CNS) lymphoma. Brain tumors (excluding lymphomas) occurring in HIV-1 infected patients have only occasionally been described. The present review summarizes these diverse tumor entities and reports on the controversial theories of a possible oncogenic potential of HIV-1. Although rare, intracerebral tumors must be considered in the differential diagnosis of an intracranial space-occupying lesion in an HIV-1 infected patient.

Dural cysts in the cervical region. Report of three cases and review of the literature

Dural spinal cysts are exceedingly rare lesions. The authors are aware of only seven cases reported in the literature. This report comprises three patients with dural cysts of the cervical spinal canal who presented with atypical neurological signs and symptoms, including a long history of dysesthesias and atrophic pareses in the proximal upper extremities. Surgical intervention disclosed two ventrally and one dorsally located cystic lesions of the spinal dura mater. The cystic wall was fenestrated and kept open by a silicone catheter in each case. Histological examination of the excised lesions revealed fibrous connective tissue consistent with dural tissue. No epithelial lining was detected. The lesions were classified as dural cysts. The patients' postoperative courses were uneventful. Although dural cysts are rare lesions, they must be considered in the differential diagnosis of spinal cystic lesions. Because they are nonaggressive and can be safely drained by microsurgical techniques, patients have a favorable prognosis. Early surgical intervention is mandatory to prevent severe neurological deficits.

Spinal epidural cavernous hemangiomas. Report of three cases and review of the literature

Epidural cavernous hemangiomas are increasingly identified as a cause of acute or chronic progressive spinal cord syndrome and local back pain or radiculopathy. The authors present three cases of spinal epidural cavernous hemangiomas manifesting as spinal cord syndrome, thoracic radiculopathy, and lumbar radiculopathy. Based on the imaging characteristics of these three cases and a review of the literature, the clinical signs and symptoms and their implications, the role of preoperative neuroradiological diagnosis, and the need for complete surgical resection are discussed. Epidural cavernous hemangiomas display consistent magnetic resonance imaging properties: T1-weighted images most commonly show a homogeneous signal intensity similar to those of spinal cord and muscle, and contrast enhancement is homogeneous or slightly heterogeneous. On T2-weighted images the signal of the lesion is consistently high and slightly less intense than that of cerebrospinal fluid. Frequently, the lesion is characterized by its extension through the intervertebral foramen. Awareness of these characteristics facilitates diagnosis and treatment of the lesions. Despite the risk of bleeding, in all three cases complete surgical excision was achieved.

Ganglioglioma of the spinal cord: report of two rare cases and review of the literature

OBJECTIVE AND IMPORTANCE

The goal of this article is to present the clinical and histopathological features of two rare cases of ganglioglioma occurring in the cervicothoracic and thoracolumbar spinal cord.

CLINICAL PRESENTATION

A 4-year-old female patient presented with tetraparesis, whereas a 54-year-old woman showed paraparesis of both feet.

INTERVENTION

Both tumors could be removed totally by microsurgical techniques. Light microscopically, the tumors in both cases showed basically identical histological features and were diagnosed as benign gangliogliomas. Postoperatively, the two patients did not show improvement. Tumor recurrence was not noted at follow-up examinations within 11 and 24 months after surgery, respectively.

CONCLUSION

Ganglioglioma must be considered in the differential diagnosis of tumors affecting the spinal cord. In cases of suspected spinal ganglioglioma showing no sharp delineation from the surrounding tissue, a subtotal tumor removal should be considered to prevent severe neurological deficits.

Colloid cysts of the third ventricle with fatal outcome: a report of two cases and review of the literature

Two cases of sudden death due to colloid cysts of the third ventricle are presented with a review of the literature. In the first case, a 40-year-old woman suffered an acute onset of severe frontal headache after an intercontinental air flight. The next day, she was found comatous and died 7 h after admission to a hospital. In the second case, a 33-year-old man with a medical history of recurrent headaches was found dead in his car. Autopsy in both cases revealed a colloid cyst of the third ventricle and hydrocephalus involving the lateral ventricles. These cases demonstrate that fatal cases still occur. Nevertheless, prompt diagnosis using computed tomography (CT) or magnetic resonance imaging (MRI) is essential, since colloid cysts are histologically benign tumors that can be removed safely by neurosurgical intervention.

The cross-sectional area of the cervical spinal canal in patients with cervical spondylotic myelopathy. Correlation of preoperative and postoperative area with clinical symptoms

STUDY DESIGN

Retrospective analysis of routine computed tomography investigations.

OBJECTIVE

To investigate whether the extent of clinical symptoms in patients undergoing surgery for cervical spinal myelopathy depends on the transsectional area of the cervical spinal canal.

METHODS

Forty-five patients underwent surgery using different techniques to enlarge the width of the spinal canal. For clinical evaluation before and after surgery, a modified score of the Japanese Orthopedic Association was used (mean follow-up period, 19.6, 9.1 months). The cross-sectional area of the spinal canal in computed tomography scans (C4-C6) was quantified 1 day before and 1 week after surgery using pixel-dependent area calculation software for three different density ranges given in Hounsfield units.

RESULTS

After surgery, a significant enlargement of the cervical spinal canal of 78.2 +/- 55.9% could be achieved. The Japanese Orthopedic Association score increased significantly by 3.7 +/- 2.2 points from a median preoperative score of 10 to a score of 14 after surgery. Patients with a preoperative Japanese Orthopedic Association score > or = 10 achieved a significantly better outcome after surgery. Conversely, no patient with a postoperative area larger than 1.6 cm2 achieved a score of less than 12 Japanese Orthopedic Association-points. No significant linear correlation, however, was found between the postoperative transsectional area and the postoperative Japanese Orthopedic Association score of all patients.

CONCLUSION

The preoperative clinical presentation of the patient was found to be the only prognostic hint for improvement after surgery. Preoperative area measurements of the spinal canal cannot be used as a prognostic tool for surgical outcome. Further, the postoperative measurements do not correlate with the clinical outcome. These data, however, which refer to C4 to C6, provide evidence that every surgical procedure to enlarge the cervical spinal canal should result in an area of 1.6 cm or more.

Primary intracranial metatypical basal cell carcinoma: case report

OBJECTIVE AND IMPORTANCE

A case of primary intracranial metatypic basal cell carcinoma in a 20-year-old man is described.

CLINICAL PRESENTATION

A 20-year-old man presented with palsies of the left cranial nerves VI through XII, including complete facial and vestibulocochlear nerve palsy and signs of cerebellar dysfunction, which included left-sided brachydiadochokinesis and nystagmus when looking to the left. There was no evidence of extracranial tumor manifestation. Imaging showed a tumor located in the left pyramidal bone, filling the left cerebellopontine cistern and compressing the brain stem with an extension into the middle cranial fossa as far as the internal carotid artery.

INTERVENTION

Subtotal tumor removal was accomplished by a combined neurosurgical-otolaryngological procedure through a transpetrosal approach. A histopathological examination revealed a metatypical basal cell carcinoma. Postoperatively, a total dose of 60 Gy of radiation therapy was administered over a period of 6 weeks.

CONCLUSION

Although it is rare, primary intracranial basal cell carcinoma should be considered in the differential diagnosis of tumors of the temporal bone.

Kaposi's sarcoma in the cerebellum of a patient with AIDS

A case of Kaposi's sarcoma in the left cerebellar hemisphere of a patient with AIDS is presented. The lesion was not detected with imaging techniques in the patient who, during the clinical course, did not show neurological signs and symptoms. This small nodular lesion was only revealed at autopsy. This rare finding is an example of the broad spectrum of central nervous system involvement in HIV-1-infected individuals.

The transcallosal interforniceal approach to the third ventricle: anatomic and microsurgical aspects

OBJECTIVE

The ability to visualize median-sagittal brain structures by magnetic resonance imaging improves planning for surgery to treat lesions of the third ventricle. The most appropriate path to the third ventricle is the transcallosal approach. The present study was undertaken to describe the surgical anatomy and landmarks encountered during this approach.

METHODS

The transcallosal-interforniceal approach was undertaken in 30 formalin-fixed brains using an operating microscope. The surface landmarks for the approach pathway were the two points, P5 and P7, located 5 and 7 cm anterior to the central sulcus, respectively. Using these two points on the cortical surface as references, a variety of measurements were made to provide quantitative information about distances between brain structures that are encountered during the surgical approach. Measurements that were made include the following: 1) the distance between P5 and the cingulate sulcus, 2) the distance between the cingulate sulcus and the corpus callosum, 3) the height of the corpus callosum, 4) the distance between the anterior commissure and the foramen of Monro, and 5) the distance between the lower margin of the corpus callosum and the fornix.

RESULTS

Mean values for these key measurements were as follows: 1) 23.96 mm (range, 15.0-32.0 mm); 2) 13.50 mm (range, 8.0-20.0 mm) with reference to P5 and 12.73 mm (range, 16.0-18.0 mm) with reference to P7; 3) 6.12 mm (range, 4.0-8.0 mm) with reference to P5 and 6.60 mm (range, 4.0-9.0 mm) with reference to P7; 4) 4.96 mm (range, 2.5-10.0 mm), independent of P5 and P7; and 5) 8.46 mm (range, 3.0-16.0 mm) with reference to P5 and 11.04 mm (range, 6.0-22.0 mm) with reference to P7.

CONCLUSION

The detailed quantitative information obtained in this study about the interforniceal approach permitted definition of surgical approach pathways that preserve important anatomic structures, such as the motor strip, genu of the corpus callosum, fornical commissure (hippocampal commissure), anterior commissure, and fornical columns. The approach through this surgical corridor can easily be planned and performed in individual cases using median-sagittal magnetic resonance imaging scans.

Endodermal cyst of the third ventricle: case report

OBJECTIVE AND IMPORTANCE

Endodermal cysts are rare lesions that primarily affect the spinal cord. Only a few reports have been published that describe intracranial endodermal cysts, and, in most of the cases, the cysts were located in the posterior fossa. To our knowledge, there have been no reports of endodermal cysts of the third ventricle.

CLINICAL PRESENTATION

A symptomatic endodermal cyst of the third ventricle in a 28-year-old man is presented. The patient demonstrated signs of increased intracranial pressure and reported a progressive loss of vision in his right eye. Neuroradiological imaging revealed obstructive hydrocephalus and a lesion inside the third ventricle measuring 1.2 cm in diameter and occluding the interventricular foramen.

INTERVENTION

The cyst was successfully removed via a transcallosal-transforaminal approach. Postoperatively, the patient developed bifrontal effusions for some days. Hydrocephalus was diminished, but his vision had only slightly improved.

CONCLUSION

To our knowledge, this is the first published report of an endodermal cyst occurring in the third ventricle, and represents a further example of the broad spectrum of lesions affecting that location.

Vascular changes in the cerebral cortex in HIV-1 infection. II. An immunohistochemical and lectinhistochemical investigation

In human immunodeficiency virus 1 (HIV-1)-infected patients, a hypoperfusion is seen by SPECT analyses in different brain regions but a specific pattern for the predominance of a specific brain region has not been found. The vessels of the cerebral cortex of the frontal, temporal, parietal, and occipital lobes of acquired immunodeficiency syndrome (AIDS) brains and control brains were analyzed by immunohistochemistry and lectin histochemistry. Immunohistochemistry was performed for collagen IV, laminin (basal lamina), and factor VIII (endothelial cell) and lectin histochemistry [Ricinus communis agglutinin (RCA-I), Ulex europaeus agglutinin (UEA-I), wheatgerm agglutinin (WGA) and soybean agglutinin (SBA)] was used to study changes of glycoproteins in the endothelial cell membrane. Vessels were counted in the gray and white matter, and their staining intensity for the different antibodies and lectins was rated using a three-point scale. Immunoreactivity for collagen IV was reduced in AIDS brains, which may be related to thinning of the basal lamina of cerebral vessels, as has previously been shown by electron microscopy. Lectin histochemistry with SBA, UEA-I and WGA indicated loss of glycoproteins in the membrane of endothelial cells. The data from the present study show morphological changes of the endothelial cells and of the basal lamina in the brain of individuals with AIDS, and might represent the morphological sequelae of a disturbed blood-brain barrier, or may account for the hypoperfusion seen in SPECT analyses.

CMV-infected subependymoma in the fourth ventricle of an HIV-1 infected patient

A case of an AIDS patient with a CMV-infected subependymoma of the fourth ventricle is presented. The tumor was incidentally found at autopsy and was not suspected during the clinical course. This is the first report of a subependymoma in HIV-1 infection. Moreover, infection of a tumor with CMV is an extremely rare condition, which has until now been described only once in an anaplastic astrocytoma.

Glycosylphosphatidylinositol-alkaline phosphatase from calf intestine as substrate for glycosylphosphatidylinositol-specific phospholipases--microassay using hydrophobic chromatography in pipet tips

An electrophoretically homogeneous glycosylphosphatidylinositol- alkaline phosphatase fraction from calf intestine, obtained by hydrophobic chromatography, was used as "enzyme-labeled" substrate for testing phospholipase activity. The reaction products were separated by (i) hydrophobic chromatography in pipet tips and (ii) Triton X-114 phase partitioning. The chromatographic method presented permits high test frequencies, does not need temperature-controlled sample handling, and is only slightly disturbed by detergents, organic solvents, and proteins. The method was used to characterize phosphatidylinositol- specific phospholipase C from Bacillus cereus and phospholipase D from calf serum. Measurement of substrate hydrolysis by phospholipases is apparently linear to enzyme concentration and time. Relative activity of both enzymes is maximum at pH 6.5, corresponding to the optimal pH range found with other glycosylphosphatidylinositol substrates and phosphatidylinositol-specific phospholipases of other sources. Maximum activity of phospholipase C was found at 0.03% Triton X-100, 0.01% Brij 35, and 0.2% n-octylglucoside. The activity is not affected by Ca(2+), NaHCO(3), o-phenanthroline, or EDTA, increasingly inhibited by MgCl(2), MnCl(2), and ZnCl(2), and slightly activated by Na+ and K+. Calf serum phospholipase D shows maximum activity at 0.05% Triton X-100, 0.02% Brij 35, and 0.4% n-octylglucoside. The apparent Km values for phospholipase C (12.25 micron) and phospholipase D (4.94 micron) found with glycosylphosphatidylinositol-alkaline phosphatase are compared with values published for other glycosylphosphatidylinositol substrates.