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Biomedical subjects

C H Davis

Publications and source records attributed to C H Davis.

At least 73 records · Page 4Linked to original sources
PubMed1983

Chlamydia psittaci elementary body envelopes: ingestion and inhibition of phagolysosome fusion.

The cell surface of Chlamydia psittaci seems important for establishing infection since (i) UV-treated elementary bodies (EB) attach to and are ingested by L cells and (ii) heat or antibody treatment decreases attachment to L cells and promotes the fusion of chlamydiae-containing phagosomes with lysosomes in macrophages. In the studies reported here, [3H]uridine-labeled UV-treated EB also persisted in mouse resident peritoneal macrophages and L cells, suggesting that phagosome-lysosome fusion is inhibited. We therefore chose to investigate the ingestion and internal fate of isolated purified EB envelopes in both nonprofessional and professional phagocytic cells. EB envelopes are internalized by target host cells as efficiently as are whole EB. Transmission electron microscopy of macrophages whose lysosomes were marked with ferritin revealed the persistence of individual envelopes in phagosomes devoid of ferritin for the 3-h observation period. In contrast, EB envelopes heated to 56 degrees C for 15 min were consistently found in ferritin-labeled phagolysosomes as early as 30 min. As another index of persistence, isolated EB envelopes were radioisotopically labeled with a Bolton-Hunter analog, [3H]N-succinimidyl propionate, and their fate as trichloroacetic acid-precipitable material was followed. A third probe, employed to detect the persistence of non-biodegradable antigen, was indirect immunofluorescence. Fluorescein-positive antigens were brightly visible for 7 days in both macrophages and L cells when they were inoculated with untreated EB or EB maintained in penicillin. But L cells inoculated with EB envelopes or EB treated with UV or chloramphenicol, all of which prevent the conversion of infectious EB into the metabolically active reticulate bodies, displayed reduced internal fluorescence by 2 days and the appearance of fluorescent material on the cell surface. This release of EB envelope material occurred in the absence of phagolysosome fusion. The data add credence to the belief that the spontaneous breakdown or autolytic enzyme release of EB envelope components must occur preparatory to the conversion of EB to reticulate bodies.

Animals↗
PubMed1983

Familial brain tumors: studies of two families and review of recent literature.

We studied two families in each of which three or more individuals were affected by brain tumors. In the first family, which had no evidence of neurofibromatosis or tuberous sclerosis, a man, his sister, and her son developed histologically proven gliomas; the man's great uncle was historically reported to have died from a brain tumor, but the exact nature of the tumor was not known. In this family two of the tumors were low grade astrocytomas of the cerebrum, whereas the third was a mixed glioma of the cerebellum. Karyotypic analysis of this tumor showed no marker chromosomes. A second family had a history of an unusual concentration of brain tumors. In one patient the tumor was a histologically verified glioma. Four other patients had historically reported brain tumors, the descriptions of which suggested gliomas. Both families showed involvement of individuals in adjacent generations, although in both instances there were skipped generations. Twins, siblings, or parents and children are the kindred groups affected in most other reported families with multiple brain tumors. The mode of inheritance of brain tumors in these two families and recent literature on the conditions associated with familial brain tumors are discussed.

Adult↗
PubMed1981

Intraventricular hemorrhage from pituitary apoplexy.

The case of a patient with a massive intraventricular hemorrhage arising from a pituitary chromophobe adenoma is described. This rare and disastrous complication was ascribed to the large suprasellar extension of the tumor and its close proximity to the floor of the third ventricle. Hemorrhage in the tumor extended along the path of least resistance and ruptured into the third ventricle. A partially treated hyperviscosity syndrome and chemotherapy for an unrelated malignancy (multiple myeloma) may have predisposed the patient to the necrosis and hemorrhage in the pituitary tumor.

Adenoma↗
PubMed1981

Cerebellar astrocytomas in children and young adults.

A clinical and pathological review of 43 cases of cerebellar astrocytomas in children and young adults was undertaken. Thirty-one of the 36 surviving patients were examined by computed tomography. Twelve patients with asymptomatic tumour were detected. Histology was necessary to identify the higher risk "diffuse" group, but no histological features helped to identify tumours liable to recur. Improvements in the prognosis may occur with long term CT scanning.

Adolescent↗
PubMed1980

Anterior sacral meningocele: two case reports and discussion of surgical approach.

Virtually all patients with anterior sacral meningocele have a pelvic mass with symptoms and signs relating to pressure of the mass on adjacent structures. Constipation is a universal complaint; urinary incontinence is common. A headache often develoips when the patient stands, due to lowered spinal fluid pressure as the meningocele sac fills. A scimitar-shaped sacrum on anterioposterior plain roentgenograms of the spine is pathognomonic. The coccyx may be absent, and the lower sacral laminate may be absent or incomplete. Myelography confirms the diagnosis and should be done with large volumes of iophendylate in order to fill the sac. Only approximately 130 anterior sacral meningoceles have been reported in the literature. This article presents 2 more cases, both seen at the North Carolina Baptist Hospital. The surgical approach to both was through a sacral laminectomy; the communicating stalk was ligated and the meningocele was removed. One patient was 11 years old and had a large suprapubic pelvic mass found on routine examination. She is neurologically normal postoperatively. The other was 7 years old and had had fecal incontinence since birth. That incontinence is less severe postoperatively and the patient is neurologaically normal.

Child↗
PubMed1980

Intervertebral disc space infection in a child presenting as a psoas abscess: case report.

Intervertebral disc space infection in children is usually a benign, self-limiting process. We report on what is, to our knowledge, the first case of discitis in a child that developed into an anterior paraspinous abscess. This 13-year-old girl had a 3-month history of low back and leg pain and low grade fever. Roentgenograms of the spine showed collapse of the L-5, S-1 interspace with destruction of the L-5 vertebral body and, on the lateral lumbar view, an anterior soft tissue mass. Computed tomography showed a paraspinous mass to the right of the L-4 and L-5 vertebral bodies. Access to a right psoas abscess was gained through a retroperitoneal abdominal approach; draining of the abscess revealed necrotic disc material extruding from the L-5, S-1 interspace. Her recovery was uneventful. The causative organism proved to be Staphylococcus aureus.

Abscess↗
PubMed1979

Ophthalmic findings in dural arteriovenous shunts.

Five cases of dural carotid arteriovenous shunts in the region of the cavernous sinus are reported. Discussion of the specific carotid angiographic features stresses the pathophysiologic characteristics of these shunts in relation to the ophthalmic findings. In all cases, the meningohypophyseal artery was involved as the sole or predominant source of the afferent arterial supply, and the degree of proptosis, epibulbar congestion and secondary glaucoma correlated with retrograde filling of the superior ophthalmic vein from the cavernous sinus. The ophthalmologist's early recognition of this entity as a "spontaneous" pathologic occurrence is important, since he is intimately involved in its diagnosis and long-term management.

Aged↗
PubMed1979

Gunshot wounds to the spinal cord.

A series of 59 patients with gunshot wounds to the spinal cord is presented. Seventeen injuries were cervical, 30 were thoracic, 11 were lumbar, and one was sacral. Twenty-nine patients had immediate complete sensorimotor loss of function, 18 had sensory or motor sparing below the cord lesions, and 12 had injury of the cauda equina. Thirty-nine patients were treated with decompressive laminectomy, four with local wound debridement only, three with cervical traction and subsequent anterior cervical fusion; 13 had only conservative therapy. Eleven patients had return to normal function and 20 patients had some degree of improvement. There was no significant difference in the outcome between patients operated on and those treated conservatively.

Adolescent↗
PubMed1979

Urea: obligate intermediate of pyrimidine-ring catabolism in Rhodosporidium toruloides.

Urea has been shown to be an obligate intermediate in and the penultimate product of the catabolism of pyrimidine-ring nitrogen in Rhodosporidium toruloides (Rhodotorula). One of a series of mutants selected for its inability to utilize uracil as a sole source of nitrogen was unable to utilize urea also. The mutant accumulated urea and failed to form 14CO2 during supplementation with [2-14C]uracil. Radioautograms from the resulting cell extracts and media failed to reveal expected intermediates. Cell-free extracts of the mutant were shown to lack urease activity. Revertants of the mutant were essentially wild type in all tested attributes. Elements of the reductive pathway for pyrimidine catabolism are present in Rhodosporidium (O. A. Milstein and M. L. Bekker, J. Bacteriol. 127: 1-6, 1976), but is has not been determined whether this pathway is involved with production of urea.

Cell-Free System↗
PubMed1976

Posterior cervical fusion in chidren.

Six cases of posterior cervical fusion with rib grafts in children are reported. Four of the children had sustained cervical spine injuries in accidents, and two had congenital absence of the odontoid. Three-level fusions (C1-3) were done in four children, and four-level fusions (C1-4) in two. One child died of unrelated causes 3 months after the operation. The other five children have been followed for 5 to 13 years. All are doing well and each has a remarkably supple, stable neck and no neurological deficit.

Adolescent↗
PubMed1975

Intracerebral schwannoma.

A case is reported in which the authors describe a rare example of an intracerebral schwannoma in a 63-year-old woman having a clinical history suggesting the presence of the tumor for 40 years. Such an unusually prolonged course is ascribed to extensive regressive changes in the tumor. The occurrence of intracerebral schwannoma indicates the existence of schwann cells deep within the brain substance, although the precise source of these cells remains obscure.

Brain Neoplasms↗