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Biomedical subjects

C Morgan

Publications and source records attributed to C Morgan.

At least 217 records · Page 12Linked to original sources
PubMed1979

Location of bladder preganglionic neurons within the sacral parasympathetic nucleus of the cat.

Sacral parasympathetic preganglionic neurons innervating the urinary bladder were labelled by applying horseradish peroxidase (HRP) to branches of the pelvic nerve at the neck of the bladder. Bladder preganglionic cells were located primarily in the intermediolateral grey matter of sacral cord segments 1, 2 and 3 and extended from the ventral end of the central canal to the inferior margin of the dorsal horn. Dendrites extended into the dorsolateral funiculus, toward the lateral edge of the dorsal horn, medially beneath the dorsal horn and ventrally within the nucleus. Although a small number of cells were found medially beneath the dorsal horn, it is concluded that the majority of bladder preganglionic neurons occupy a lateral position within the sacral parasympathetic nucleus.

Animals↗
PubMed1979

Digital radiography using a computed tomographic instrument.

A prototype computed radiography (CR) system was evaluated for its efficacy as an independent diagnostic modality. Preliminary measurements of high contrast resolution, low contrast perceptibility, and dose were obtained. Clinical examinations including skull, abdomen, liver, gallbladder, biliary system, spine, and extremities were performed as an adjunct to either computed tomography or CR. The data suggest that CR can be an effective diagnostic imaging modality by itself. Advantages over conventional radiography include high scatter rejection, low patient dose, wide dynamic range, and good low contrast sensitivity for large objects; disadvantages, its long exposure time and relatively poor high contrast spatial resolution.

Biliary Tract↗
PubMed1979

Effect of intermittent exposure to 3% CO2 on respiration, acid-base balance, and calcium-phosphorus metabolism.

One subject was exposed for six days to increasing levels of CO2, rising at a constant rate from 0.03 to 3.0% CO2 within a 15-h period followed by 9 h of air breathing. To assess acid-base parameters, arterialized capillary blood was taken from a finger twice daily (at 8 a.m. and 11 p.m.) at times corresponding to the beginning and end of the intermittent exposure to CO2. Venous blood samples were obtained on alternate days at the same times. Urine specimens were collected twice daily. The subject was on a liquid diet. Resting respiratory minute volume (VE), oxygen consumption (VO2), carbon dioxide excretion (VCO2), alveolar carbon dioxide and oxygen tension (PACO2) and PAO2) were measured twice daily. PACO2 and PAO2 were also determined at the end of breath-holding twice daily; CO2 tolerance tests and lung function tests were also carried out. In contrast to the effects of chronic exposure to 3% CO2, the CO2 tolerance tests showed an increased sensitivity (increase of slope) and breath-holding PACO2 did not change, indicating that acclimatization to CO2 did not develop. The ventilatory response to CO2 was not sufficient to prevent CO2 accumulation in the body; this accumulation was eliminated during the nightly air-breathing periods on the fourth and fifth days, indicated by higher values of PaCO2 and PACO2. The known renal response to hypercapnia, consisting of an increased excretion of titratable acidity, ammonia, and hydrogen ion excretion, occurred but was interrupted after the first day and was triggered again on the fourth and fith days when accumulated CO2 was released from body CO2 stores. The second renal response was associated with a marked calcium excretion, which suggests that bone CO2 stores were involved.

Acid-Base Equilibrium↗
PubMed1977

The effect of biopsy-hole shape and size on bone strength.

Investigation in cadaver femora of the relationship between the shape or size of a hole made in the cortex and the breaking strength of the bone revealed that of the shapes studied, an oblong hole with rounded ends afforded the greatest residual strength. Furthermore, we found that increasing the width of the hole caused a significant reduction in strength, while increasing the length did not.

Biopsy↗
PubMed1976

The insertion of DNA into vaccinia virus.

Cells infected with vaccinia virus in the presence of hydroxyurea (HU), which blocks DNA replication, were examined in thin sections by electron microscopy at intervals after removal of HU. Dense, fibrillar material was observed at the orifice formed just before closure of the membrane constituting the envelope of the immature form of the virus. It is concluded that synchrony of assembly enabled stages in the condensation and insertion of viral deoxyribonucleoprotein to be observed. The mechanism appears to be similar to that encountered in morphologic studies of herpes simplex virus and in biochemical studies of poliovirus, adenovirus, and several bacteriophages.

DNA, Viral↗
PubMed1975

Electron microscopic studies on assembly of herpes simplex virus upon removal of hydroxyurea block.

The release of hydroxyurea-treated, herpes simplex virus-infected cells from the drug-induced block resulted in the prompt assembly of infectious virus. Electron microscope observations at sequential intervals following removal of the drug revealed considerable synchrony of replication. This synchrony permitted stages in the complex process of core assembly to be examined in detail. The data suggest that after partial or complete assembly the nucleoprotein enters the differentiated capsid to become enfolded.

Cell Nucleus↗
PubMed1975

Effect of chronic hypercapnia on body temperature regulation.

Guinea pigs and rats exposed to 15% CO2 for 7 days showed a parallel time course of changes in pH, body temperature (TB), and oxygen consumption (VO2). Between 1 and 6 h of exposure the maximal drop in actual pH occurred in guinea pigs simultaneously with the maximal fall in TB and VO2. During the subsequent period pH TB, VO2 rose again. Skin blood content (heat loss) also exhibited a biphasic pH-dependent time course. Animals showing no partial compensation of respiratory acidosis during 3 days exposure also failed in raising their TB back to normal in this time. The behavior of TB was found to be a good indicator of the acid-base status and adaptive potential of the animals to hypercapnia. Similar results were obtained in rats. Thermo-regulatory processes in the hypothalamus were affected during exposure to 15% CO2. Both guinea pigs and rats showed a decrease in norepinephrine content of the hypothalamus during the first part of exposure reaching a maximal fall at the end of 24 h. The serotonin content increased slightly during this period. During prolonged exposure to 3% CO2 for 7 days, TB showed a transient rise, and VO2 was slightly elevated.

Adaptation, Physiological↗
PubMed1975

Vocational potential assessment.

Determination of employment potential will become increasingly important in the foreseeable future, largely due to pending Federal legislation which relates to welfare reform. The heretofore "permanently and totally disabled versus able-bodied" principle in welfare reforms is being abbandoned. Pending legislative proposals dealing with welfare reform provide for considering physically impaired persons as partially disabled and partially employable simultaneously. Thus, the need to systematically and effectively assess physically impaired citizens' capacities to participate in the job market will increase. Unquestionably, rehabilitation medicine in general, and the emerging art and science of vocational evaluation in particular, will contribute much to supplying these services. While it is widely acknowledged that the vocational potential of physically impaired persons should be evaluated in an organized manner, there are differences of opinion among professional evaluators as to which approach, or approaches, are the most meritorious; The four principal approaches are: (1) mental testing, (2) work sampling, (3) situational analysis, and (4) job tryouts. Each of these approaches is explained, contrasted, and evaluated in this paper.

Disability Evaluation↗