Biomedical subjects
Publications and source records attributed to N Carroll.
Two patients are described with Charcot-Marie-Tooth disease and chronic peripheral neuropathy. Both had dyspnoea, orthopnoea, and evidence of severe diaphragm weakness. Expiratory muscle function was well preserved and abnormalities of gas exchange during sleep were only minor.
We studied six patients with isolated bilateral paralysis or severe weakness of the diaphragm, present for 2 to 60 months (mean = 25), to document the clinical and respiratory sequelae of the condition. Severe diaphragm dysfunction was confirmed by the demonstration of the very low maximal transdiaphragmatic pressure (Pdi) generated by either a sniff (13 +/- 6 cm H2O, normal 148 +/- 24) or a static inspiration (11 +/- 8, normal 108 +/- 30) and during bilateral phrenic nerve stimulation (0.8 +/- 2.0, normal 22 +/- 4). Resting arterial blood gases were normal (SaO2 = 95 to 97%) and no oxygen desaturation occurred during maximal exercise on a treadmill. Maximum voluntary ventilation was low and related to PImax (r = 0.89). Overnight sleep monitoring showed that time spent in rapid eye movement sleep was normal (mean 55 +/- 36 min, range 26 to 117 min). Mean maximum increment in transcutaneous CO2 was within normal limits (6 +/- 2 mm Hg, range 3 to 9 mm Hg). Three patients had occasional brief episodes of oxygen desaturation (mean maximal decrease 13 +/- 10%, range 2 to 27%); however, only two of these spent a measurable proportion of total sleep time (TST) with an SaO2 of less than 80% (1% and 3% TST, respectively). No patient has developed any symptoms of nocturnal hypoventilation or chronic respiratory failure during periods of observation of up to five yr. We conclude that bilateral paralysis or very severe weakness of the diaphragm does not of itself lead to respiratory failure unless weakness of other respiratory muscles is present.
A patient with extensive pulmonary tuberculosis developed hypercalcaemia following rifampicin-induced interstitial nephritis.
To assess ultrastructural alterations to the corneal endothelium, eye drops containing vehicle alone or vehicle plus 0.004% thimerosal with or without 0.1% disodium ethylenediaminetetraacetate (Na2EDTA) were administered hourly over a 2-day period to rabbit corneas in vivo. Twenty of the corneas received a 5-mm keratectomy that removed epithelium and superficial stroma and 10 corneas were left intact. The vehicle alone had no effect on the endothelium of normal corneas. Thimerosal drops with or without Na2EDTA caused some clarification of the cytoplasm and dilatation of the endoplasmic reticulum of endothelial cells. The mitochondria had dilated cristae and membrane condensations. After keratectomy and vehicle only drops, the central endothelium showed a marked increase in microvilli and mitochondrial changes. Addition of either thimerosal or thimerosal plus Na2EDTA resulted in a slight decrease in membrane activity but an increase in intracellular edema and dilatation and damage to organelles. The peripheral areas were less affected than the center. Although the endothelium was stressed, most changes were considered reversible.
Total serum tryptophan concentrations were measured in 74 cataractous patients and 124 controls. No significant differences were observed in the mean values for the cataractous and normal subjects, 11.4 +/- 2.6 and 11.3 +/- 2.2 micrograms/ml respectively, or in the range of values, 7.4-17.1 and 7.3-17.4 micrograms/ml respectively. These results do not support previous reports that serum tryptophan is elevated in cataractous subjects.
Studies were made comparing the corneal endothelium of bisected human corneas; one half of each was mechanically agitated in McCarey-Kaufman (M-K) medium, while the other half remained static in M-K medium for an equal period of time. Scanning electron microscopic (SEM) analysis of the corneal endothelium suggested that the endothelium of the corneas undergoing agitation does not show deterioration in morphology when compared with the non-agitated group. This finding is significant as donor corneas are now being transported in greater numbers.
Visceral glomerular epithelial cell lesions--microvillus formation, loss of foot processes, osmiophilic inclusion droplets, balloon-like malformation of cell processes, degeneration, necrosis, and loss of cell processes from capillary basement membranes--are found in rat renal isografts 1 mth after transplantation. The lesions, which are most readily recognized in perfusion-fixed material, are essentially focal, affecting neither all glomeruli, nor all cells in any glomerulus, bear no relation to the degree of interstitial nephritis in the graft, and are associated with albuminuria and with focal capillary sclerosis in some glomeruli. They are not restricted to renal isografts but are found in aging rats, in different experimental models of glomerular disease and in clinical glomerular disorders, again in association with proteinuria and glomerulosclerosis. It is therefore proposed that glomerular epithelial cell damage increases capillary permeability and impairs maintenance of the integrity of the capillary wall, leading to proteinuria and focal glomerulosclerosis.
Ten normal and 20 keratectomised corneas received hourly drops of vehicle with or without benzalkonium chloride (0.02% BAC or 0.01% BAC plus 0.1% disodium ethylenediaminetetraacetate) over the daylight hours of 2 days (18 applications). When applied to the intact cornea, BAC with or without Na2EDTA caused only slight clarification of the endothelial cytoplasm, whilst in a few mitochondria the cristae were displaced. In the keratectomised corneas receiving BAC, the majority of mitochondria of the central endothelial cells were pale and swollen or even disrupted. Many contained aggregations of membranous material either within the mitochondrion or at its outer membrane. The peripheral endothelium was much less affected than the central area of endothelium behind the keratectomy. These results suggest that BAC should not be administered to corneas in which the anterior epithelial barrier is incomplete.
A patient with Parkinson's disease developed a non-ketotic hyperosmolar diabetic coma precipitated by chest infection. Initial improvement from treatment with intravenous insulin, ampicillin and fluid therapies was followed by severe deterioration and hypovolaemic shock. Further improvement occurred only when therapy directed against Gram-negative sepsis was added. A barium examination later demonstrated aspiration of oral contents with pulmonary soilage. The differences between the easily recognized early fulminating 'aspiration syndrome' caused by aspiration of gastric contents of low pH and the aspiration of oral contents, which may remain occult for many hours, is highlighted. Life-threatening Gram-negative or anaerobic infection may then occur but remain undiagnosed because the original aspiration of foreign material is unsuspected.
A granulomatous reaction was identified in six corneal buttons obtained from patients with herpetic stromal keratitis. The inflammation, characterized by lymphocytes, plasma cells, macrophages and multinucleate giant cells, was associated with Descemet's membrane in five cases and with a break in Bowman's membrane in one case. The ultrastructural changes were documented by scanning electron microscopy in all cases. Transmission electron microscopy, performed in four cases, failed to disclose the presence of viral inclusions. Immunoperoxidase stains utilizing antibodies to the herpes simplex virus were done on all cases. Positivity (the presence of herpes simplex virus antigen or herpes simplex-like antigen) was detected within epithelium (three cases), within stroma (three cases), and within some inflammatory cells of the granulomatous reaction at Bowman's membrane. Positive staining was not detected in cells of the granulomatous reaction at Descemet's membrane. These results suggest that the reaction at Descemet's membrane, which has been found in a variety of corneal conditions, may be due to a poorly understood alteration in the antigenicity of Descemet's membrane.
A previously well 36 year old man presented with cardiac tamponade as the initial manifestation of systemic lupus erythematosus. This diagnosis should, therefore, be considered not only in cases of pericarditis but also in those of tamponade.
Energy dispersive X-ray analysis is recognized as a most useful technique in research. Its diagnostic applications are being rapidly developed. We describe a case of corneal, lenticular and retinal damage in an eye without a documented history of trauma. Scanning energy dispersive X-ray analysis of foreign material in the lens helped to elucidate the probable cause of the injury. The medico-legal implications of this case are briefly discussed.
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Thirteen infants, 2 to 10 months of age, developed hypochloremic alkalosis (serum chloride 59 to 92 mEq/l) while taking Neo-Mull-Soy (Syntex), a soy-based formula low in chloride (measured to be 0 to 2 mEq/l) but with considerable potassium citrate. Range of symptoms included lethargy, anorexia, mild spitting up, diarrhea, hematuria, and growth failure. Urine chloride excretion was less than 3 mEq/l. Plasma renin activity or aldosterone, measured in six infants, was elevated. All responded promptly to supplemental salt. One infant receiving Neo-Mull-Soy redeveloped alkalosis when supplemental salt was discontinued. Two of nine apparently normal infants receiving Neo-Mull-Soy also had hypochloremia (85, 86 mEq/l). Three of four receiving Prosobee (Mead Johnson; Cl content 7 mEq/l) had urine chloride concentration less than 20 mEq/l. The chloride content of some infant formulas is insufficient to offset salt losses following mild stress.
We developed two additions to a new system of microsurgery for corneal cutting and grafting: a 10-mm contact lens corneal cutter and a stereotaxic donor disk chuck and frame.
Tissue cultures were established from 6 retinoblastomas and the cultured cells examined by scanning electron microscopy. Cells from cultures of normal fetal retinal and glial tissue were also examined by SEM. Though a number of different cell types were found to coexist in the retinoblastoma cultures, most had the features of cells of either glial or neuronal origin. Evidence of further differentiation of cells in each series was seen. These findings indicate that the cell of origin in retinoblastoma is a multipotential stem cell which, though neoplastic, is still capable of differentiation into both glial and neuronal series.
Iliac osteomyelitis was diagnosed, in many cases after considerable delay, in twenty (2.3 per cent) of 867 children with hematogenous osteomyelitis. In ten patients coagulase-positive Staphylococcus aureus was identified. The symptoms and signs of iliac osteomyelitis depend on the direction of spread of the inflammation. The children presented with one of these syndromes: gluteal, abdominal, or lumbar disc. The diagnosis can be established early be careful physical examination: manual compression of the pelvis produces pain on the affected side, and palpation reveals tenderness over over the site of infection. The inflammatory process can be located even in early cases on a bone scan with radioactive technetium. When diagnosed early, the infection can be cured with intensive intravenous antibiotic therapy alone.
After preliminary testing with pig, dog, rabbit, monkey, cat, and human cadaver eyes the CLCC system has been used for penetrating and lamellar keratoplasty in human subjects. Clinical experience covers a broad range of corneal pathology. Detailed operative instructions and observations are given. In the experimental situation the CLCC is being used to achieve deep lamellar corneal dissection for a continuing study of non-penetrating keratoplasty.