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Biomedical subjects

D J Armstrong

Publications and source records attributed to D J Armstrong.

At least 19 recordsLinked to original sources
PubMed2006

Vitamin D deficiency is associated with anxiety and depression in fibromyalgia.

Fibromyalgia is a complex problem in which symptoms of anxiety and depression feature prominently. Low levels of vitamin D have been frequently reported in fibromyalgia, but no relationship was demonstrated with anxiety and depression. Seventy-five Caucasian patients who fulfilled the ACR criteria for fibromyalgia had serum vitamin D levels measured and completed the Fibromyalgia Impact Questionnaire (FIQ) and Hospital Anxiety and Depression Score (HADS). Deficient levels of vitamin D was found in 13.3% of the patients, while 56.0% had insufficient levels and 30.7% had normal levels. Patients with vitamin D deficiency (<25 nmol/l) had higher HADS [median, IQR, 31.0 (23.8-36.8] than patients with insufficient levels [25-50 nmol/l; HADS 22.5 (17.0-26.0)] or than patients with normal levels [50 nmol/l or greater; HADS 23.5 (19.0-27.5); Kruskal-Wallis ANOVA on ranks p<0.05]. There was no relationship with global measures of disease impact or musculoskeletal symptoms. Vitamin D deficiency is common in fibromyalgia and occurs more frequently in patients with anxiety and depression. The nature and direction of the causal relationship remains unclear, but there are definite implications for long-term bone health.

Adult↗
PubMed2006

90% pump depletion and good beam quality in a pulse-injection-seeded nanosecond optical parametric oscillator.

We measured 90% pump depletion in a singly resonant image-rotating nanosecond optical parametric oscillator that was pulse-injection seeded by a self-generated signal pulse. The oscillator was pumped by an 8 ns duration single-frequency 532 nm pulse from an injection-seeded Q-switched Nd:YAG laser and resonated an 803 nm signal. The pump and pulsed-seed beams had flat-topped spatial fluence profiles with diameters of approximately 6 mm, giving a cavity Fresnel number at 803 nm approaching 400. The beam cleanup effects of the image-rotating cavity produce a far-field signal spatial fluence profile with approximately 60% of its energy falling within the diffraction-limited spot size.

Journal Article↗
PubMed1999

Systemic vasculitis and aneurysm formation in the Wiskott-Aldrich syndrome.

A 24 year old male who suffered from the Wiskott-Aldrich syndrome developed intra-abdominal bleeding on two occasions. Radiological investigations showed aneurysmal dilatation of branches of the hepatic and superior mesenteric arteries. The second abdominal bleed necessitated laparotomy and the bleeding was localised to the kidneys. Right nephrectomy was performed and histological examination showed a necrotising vasculitis, mainly involving medium and small sized renal blood vessels. Steroids, immunosuppressive treatment, and control of blood pressure resulted in resolution of the vasculitic process and prevented further haemorrhage. Vasculitis and aneurysm formation are rarely described complications of Wiskott-Aldrich syndrome and may account for the life threatening haemorrhage which occurs in this condition.

Adult↗
PubMed1998

Melanoma-in-transit presenting as panniculitis.

Malignant melanoma presenting as an inflammatory skin metastasis has been described but is an exceedingly rare phenomenon. We report an unusual case of a patient who developed right leg lesions that were initially thought to be infectious in origin. There was no resolution of these lesions with antibiotic therapy, and the patient subsequently underwent an incisional biopsy that showed atypical S-100 positive cells within dermal vessels. On further questioning, the patient revealed that 20 years earlier she had a pigmented lesion removed from her right posterior calf. Review of that material revealed malignant melanoma, approximately 3.2 mm in depth. Although the patient was subsequently treated with a right groin lymph node dissection and isolated limb perfusion chemotherapy, she has continued to develop locally recurrent disease. This case is unusual both in terms of clinical presentation and interval of disease progression.

Aged↗
PubMed1998

Acquisition, storage, and review of safety data from a commercial system for high temperature, short time pasteurization.

A high temperature, short time (HTST) pasteurization system was equipped with electronic sensors to determine the temperature, pressure, flow rate, and position of the flow diversion valve. A computer for data acquisition was wired to the sensors to monitor and to record processing conditions related to public health. The processing conditions were stored in safety files on the hard drive of the computer, transferred weekly to a tape drive, and stored. The processing conditions of the HTST system were monitored for 270 d to determine the accuracy and reliability of the data acquisition system. The size of the HTST safety files ranged from 6.2 to 9.1 MB when the sensors were monitored every second. The file size was reduced to < 1.8 MB when the monitoring frequency was increased to every 5 s. To determine accuracy, the temperatures recorded by the data acquisition system were compared with the temperatures recorded by an electronic recorder controller. To determine reliability, changes in the position of the flow diversion valve were examined to identify process deviations and were compared with the event marker on circular charts. The review of the data file by the actual time method was an effective alternative to the electronic recorder controller for monitoring the completeness of data in the safety files. Off-line review to determine reliability required approximately 10 min/d of records.

Animals↗
PubMed1997

The relative ability of human papillomavirus type 6 and human papillomavirus type 16 E7 proteins to transactivate E2F-responsive elements is promoter- and cell-dependent.

The human papillomavirus 16 E7 protein (HPV 16 E7) transactivates the adenovirus E2 promoter (AdE2) by altering interactions between retinoblastoma (pRb) family members and the transcription factor E2F. To understand factors limiting the oncogenic potential of HPV 6, the relative ability of HPV 6 E7 as compared to HPV 16 E7 to transactivate the AdE2 promoter was determined. In primary baby rat kidney cells and human foreskin keratinocytes, HPV 16 E7 transactivated the AdE2 promoter to a greater extent than HPV 6 E7, consistent with the observation that HPV 16 E7 binds pRb with greater affinity. HPV 6 E7 gain of function correlated with increasing the affinity of the HPV 6 E7 pRb binding site of conserved region 2 (CR2). In keratinocytes, in contrast to the AdE2 promoter, the abilities of the two E7 proteins to transactivate the B-myb promoter, a promoter regulated by E2F bound to p107/p130, were comparable. Introducing a negative charge into the N-terminus (CR1) and a high affinity pRb binding site into CR2 of HPV 6 E7 resulted in a transactivator with greater activity than HPV 16 E7 for both the AdE2 and B-myb promoters. Both of the promoters were negatively regulated by E2F and transactivation by the E7 proteins required an intact E2F site. In C33-A cells, which contain a mutated pRb, the two E7 proteins had comparable transactivating activity on both the AdE2 and B-myb promoters. The data are consistent with the interpretation that HPV 16 E7 affects interactions of pRb and p107/p130 with the E2F transcription factor, whereas HPV 6 E7 only affects interactions of p107/p130.

Amino Acid Sequence↗
PubMed1997

Automated control and monitoring of thermal processing using high temperature, short time pasteurization.

High temperature, short time pasteurization was used to evaluate a computer-based system for controlling the pasteurization process, acquiring data, and monitoring records. Software was used for the control of hot water temperature, flow rate through the centrifugal timing pump, and diversion of under-processed product. Three types of control strategies were conducted: single loop, cascade, and multivariable. The single loop control strategy showed the most rapid responses to temperature changes, but the temperature response curve was slowest to return to its set point. The cascade control strategy showed slower recoveries to temperature changes, but the temperature response curve was smoother. The multivariable control strategy responded slightly faster than the cascade control strategy, and the temperature response curve was slightly smoother than the cascade control strategy. The multivariable control strategy was able to control the flow diversion valve by the use of a lethality controller. The data acquisition system, used to monitor the data obtained from the high temperature, short-time pasteurization system, was within +/- 0.1 degree C of the temperature recorded by the safety thermal limit recorder. Reliability was determined by examining the changes in the position of the flow diversion valve to identify process deviations and by comparing the changes to the event marker on circular charts. The data acquisition system was an effective alternative for monitoring the completeness of data.

Animals↗
PubMed1996

Influence of pH on the release of propranolol hydrochloride from matrices containing hydroxypropylmethylcellulose K4M and carbopol 974.

The dissolution of propranolol hydrochloride from matrices containing hydroxypropylmethylcellulose K4M (HPMC K4M) and carbopol 974 has been investigated using 0.1 M hydrochloric acid or phosphate buffer at pH 4.5 or pH 7.5. In 0.1 M hydrochloric acid, HPMC K4M predominantly controlled release since carbopol has a low solubility at this pH. As the pH increased, the carbopol became increasingly ionized and interacted with propranolol hydrochloride to form an insoluble complex which retarded the release of the drug. In addition, the nature of the interaction between carbopol 974 and HPMC K4M altered. DSC and viscometric studies indicated that the two polymers contributed synergistically to the gel network at pH 7.5. Thus at pH 7.5 polymers contributed to matrix integrity and to the control of drug release.

Acrylic Resins↗