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Biomedical subjects

C Dean

Publications and source records attributed to C Dean.

193 records · Page 11Linked to original sources
PubMed1982

Genome Expression during Normal Leaf Development : I. CELLULAR AND CHLOROPLAST NUMBERS AND DNA, RNA, AND PROTEIN LEVELS IN TISSUES OF DIFFERENT AGES WITHIN A SEVEN-DAY-OLD WHEAT LEAF.

Changes in genome expression during normal cellular and plastid development in the first leaf of young (7-day-old) wheat (Triticum aestivum var. Maris Dove) were investigated by examining homogeneous populations of leaf cells and plastids of several developmental ages present in the same leaf. The cells were characterized over a period immediately following the last cell division. All of the leaf cells had cytoplasmic contents and nuclei, and between 44% (young tissue) and 54% (older tissue) of the leaf cells were mesophyll cells. Chloroplast development was complete 36 hours after the chloroplasts had ceased dividing. Extremely large changes occurred in cellular constituents over a very short period of leaf development. Maximum rates of accumulation of ribulose bisphosphate carboxylase per mesophyll cell (80 picograms/hour), chlorophyll per mesophyll cell (9 picograms/hour), and 70S ribosomes per mesophyll cell (19 x 10(5)/hour) were recorded.Total cellular DNA varied from 40 to 60 picograms/cell, reflecting the changes in nuclear and chloroplast DNA synthesis during different phases of cellular and chloroplast division. The period of maximum accumulation of protein, total RNA, and both 80S and 70S ribosomes occurred between 36 and 48 hours after the last cell division. Between 48 and 60 hours, 70S rRNA per cell and protein content per cell continued to increase as 80S rRNA per cell declined. Ribulose bisphosphate carboxylase per cell increased 20-fold between 15 and 60 hours.

Journal Article↗
PubMed1982

Genome Expression during Normal Leaf Development : 2. Direct Correlation between Ribulose Bisphosphate Carboxylase Content and Nuclear Ploidy in a Polyploid Series of Wheat.

The quantitative relationships between ribulose bisphosphate carboxylase, nuclear ploidy, and plastid DNA content were examined in the nonisogenic polyploid series Triticum monococcum (2x), Triticum dicoccum (4x), and Triticum aestivum (6x). Ribulose bisphosphate carboxylase per mesophyll cell increased in step with each increase in nuclear ploidy so the ratios of ribulose bisphosphate carboxylase per mesophyll cell (picograms) to nuclear DNA per mesophyll cell (picograms) were almost identical in the three species. Ribulose bisphosphate carboxylase per plastid was 14.1, 14.7, and 16.8 picograms in the 2x, 4x, and 6x ploidy levels, respectively. Plastid area in these three species decreased with increasing nuclear ploidy so the concentration of ribulose bisphosphate carboxylase in the plastoids was 60% higher in the hexaploid compared to the diploid species. DNA levels per plastid were 64 and 67 femtograms for the diploid and tetraploid species, respectively, but were 40% less in the plastids of the hexaploid species. These relationships are discussed in terms of cellular and plastid control of ribulose bisphosphate carboxylase content.

Journal Article↗
PubMed1981

The social and obstetric correlates of psychiatric admission in the puerperium.

Computer linkage of obstetric and psychiatric record systems made it possible to identify all women resident in the city of Edinburgh who had given birth to live or stillborn children in 1971-7 and to study (a) the distribution of psychiatric admissions relative to the time of childbirth and (b) the correlates of psychiatric admission in the first 90 days after childbirth. Having a first baby, being unmarried and undergoing Cesarean section were all associated with an increased risk of admission; twin births, perinatal death and maternal age were not. It is difficult to account for these and other established relationships purely in psychological or purely in somatic terms, suggesting that influences of both kinds are probably involved in the genesis of puerperal disorders.

Adolescent↗
PubMed1981

The symptomatology of puerperal illnesses.

Women who had a psychiatric illness requiring hospital admission within 90 days of delivery were compared with a control group matched for age, Research Diagnostic Criteria diagnosis and year of admission. Those with a diagnosis of major depressive disorder differed significantly from non-puerperal controls in being more deluded or hallucinated, more labile and more disoriented. There was no difference between puerperal and control cases of major depressive or manic disorder with respect to treatment received, or responded to, or length of stay in hospital.

Adolescent↗
PubMedDate not supplied

A histological reconstruction of dental development in the common chimpanzee, Pan troglodytes.

Much is known about the dental development of Pan compared with that for other extant great apes. The majority of information available has concentrated either on the emergence times of teeth or on the sequence of mineralization stages of the teeth as revealed from radiographs. However, the problems of defining stages of tooth formation sufficiently accurately on radiographs are only now becoming recognized. All of the data available to date suggest the presence of a more variable picture for the timing of mineralization stages in chimpanzees than for the timing of tooth emergence. In particular, arguments persist in the literature over the time of initial mineralization and the time it takes to form each anterior tooth crown in chimpanzees. Therefore we attempt to provide a more precise chronological time scale for dental development in our closest living relative. Furthermore, we examine the sequence of molar cusp formation relative to enamel formation times related specifically to those cusps and to try to tie these data in with information from functional studies of molar crowns. Histological sections of 14 maxillary and 28 mandibular teeth from four chimpanzee (Pan troglodytes) individuals and three molar teeth from three chimpanzees of unknown origin were prepared in accordance with a well-established protocol. By combining data on short-period and long-period incremental lines (including daily secretion rates, periodicity, prism lengths and enamel thickness) in both enamel and dentine, we reconstruct times for the onset and duration of crown formation as well as construct a schedule for the pattern and timing of dental development in this one hominoid species. Interestingly, our histologically-derived data confirms that the data from radiographic studies underestimate crown formation times by the following amounts for each tooth type: I1 2.5 years, I2 3.1 years, C 1.6 years, P3 1.9 years, P4 0.1 years, M1 0.8 years, M2 1.1 years and M3 0.3 years. When combined with data on gingival emergence, it seems that chimpanzee teeth have a greatly reduced time for root growth before emergence occurs and that the major differences between Homo sapiens and Pan lie in the first part of the root formation rather than in the total period of crown formation. Maxillary and mandibular molar functional cusps take longer to complete enamel formation to the cervix than any other cusp in that same tooth, which makes sense as these cusps are thick enamelled. These results suggest that new links can be made between developmental aspects, occlusal morphology and tooth function.

Aging↗
PubMedDate not supplied

A role for serotonin in the elaboration of a differential pattern of activity in sympathetic nerves to kidney and skeletal muscle vasculature.

The role of serotonin (5-HT) in the elaboration of patterns of regional sympathetic discharge evoked from the ventral medulla was examined in cats under Saffan anesthesia. A differential response pattern consisting of an increase in renal sympathetic nerve activity simultaneous with no change in activity to skeletal muscle vasculature was evoked from a group of ventral medullary neurons by microinjection of D,L-homocysteic acid. Subsequent intrathecal administration of the 5-HT receptor antagonist methysergide (200 micrograms) attenuated or abolished the excitatory response to the kidney on restimulation of the medulla, without affecting sympathetic activity to muscle. Methysergide did not affect an excitatory response evoked in the outflow to both the kidney and skeletal muscle vasculature from an adjacent region of the ventral medulla. These results indicate a role for 5-HT in the elaboration of a specific differential pattern of sympathetic response evoked from medullary neurons.

Animals↗
PubMedDate not supplied

Health-related quality of life tools for venous-ulcerated patients.

Healthcare manufacturing companies have developed many new and novel materials for wound care. They claim that the dressing materials will improve the healing progress of the wound or have a therapeutic value and have sought to assess their efficacy and effectiveness in clinical trials. These claims should be clearly supported by the perspectives of those who actually use the devices. Compression therapy, which is regarded as an effective treatment for venous leg ulcers, is far from ideal owing to a number of limitations that it possesses, such as patient discomfort, difficulty experienced in applying correct compression on the limbs, choosing a correct dressing for the wound or finding differences between the performance of various devices. It is necessary to investigate the patient's views and perspectives while randomized controlled clinical trials are conducted. In this review the concept of quality of life (QoL) and the tools used to measure QoL and studies that were conducted with patients suffering from chronic venous leg ulcers and undergoing therapy are considered, along with contributory factors to the healing process. In addition, a questionnaire modified from the original format is recommended as the suitable tool for assessing the QoL of patients suffering from venous leg ulcers while participating in clinical trials.

Bandages↗
PubMedDate not supplied

Peroneal afferent nerve discharges underlying the behavioral response to the formalin test.

BACKGROUND AND OBJECTIVES: Subcutaneous injection of formalin into the hindpaw of the rat results in a biphasic behavioral response consisting of flinching of the injected paw. It is postulated that the second-phase response is related to sensitization of spinal cord neurons rather than to resumption of peripheral nociceptor activity. METHODS: On removal from anesthesia with 3% halothane, 10 rats were given a subcutaneous injection of formalin (5%, 50 microL) into the dorsum of the hindpaw. Behavioral response to the formalin test were observed for the subsequent hour. In five sodium pentobarbital-anesthetized rats, peroneal afferent nerve activity was recorded for 1 hour following similar subcutaneous injection of formalin. RESULTS: During standard formalin testing in unanesthetized rats, flinching peaked between 1 and 2 minutes following injection (phase 1 response), ceased between 5 and 10 minutes, and recommenced after 15 minutes with a second peak at 45 minutes (phase 2). In sodium pentobarbital-anesthetized rats, peroneal afferent nerve activity increased transiently during the time course of the phase 1 behavioral response but showed no subsequent increase in activity during the ensuing 55 minutes. CONCLUSIONS: The results are consistent with the hypothesis that the initial behavioral response to formalin injection is mediated by high peripheral nerve activity, while the second phase is mediated by sensitization of dorsal horn neurons in conjunction with low persistent levels of afferent activity.

Animals↗