Biomedical subjects

T T Aoki

Publications and source records attributed to T T Aoki.

95 records · Page 6Linked to original sources

PubMedDate not supplied

The heated dorsal hand vein: an alternative arterial sampling site.

Studies of substrate flux, isotope activity and metabolic balance frequently require arterial sampling. We evaluated: (1) whether substrate concentrations obtained from heated dorsal hand veins (HDHV) were comparable to samples obtained from the radial artery, (2) whether heat sufficient to arterialize HDHV altered contralateral forearm blood flow thus affecting flux calculations, (3) whether a +14 heating pad equaled a cumbersome +700 heating chamber, and (4) whether HDHV showed a dose-response curve to varying heat loads. In 12 normals, dorsal hand temperature was raised from 31.8 +/- 0.6 degrees C to 39.8 +/- 0.8 degrees C (chamber) and 39.3 +/- 0.3 degrees C (pad). Basal contralateral forearm blood flow (3.37 +/- 0.7 ml/100 ml tissue/min) was not significantly altered in the chamber (3.39 +/- 0.5 ml) or the pad (3.44 +/- 0.5 ml). Skin temperature of the unheated hand, an index of superficial blood flow (31.5 +/- 0.7 degrees C) did not change significantly in the chamber (31.6 +/- 0.7 degrees C) or the pad (31.2 +/- 0.7 degrees C). Forearm blood flow did not change with heating in eight postoperative patients. Comparative arterial and HDHV blood gases and 10 metabolic substrates from simultaneously drawn samples at various temperatures showed HDHV PO2 approached but did not equal arterial PO2 at temperatures greater than 39 degrees C. Glucose, amino acid, and substrate concentrations were comparable at 39 degrees C and did not change with increasing temperature. HDHV can reliably determine arterial substrate concentrations using an inexpensive heating pad. In cool environments (20-22 degrees C), contralateral forearm blood flow is not significantly altered. There is no benefit to heating the hand above 39 degrees C.

Adult↗

PubMedDate not supplied

The effect of strict control with the artificial beta-cell on plasma lipid levels in insulin-dependent diabetes.

The artificial beta-cell can establish normoglycemia within 2 h in an indifferently controlled diabetic patient. In the present study, the temporal relationship between the achievement of normoglycemia and its effect on plasma lipid concentrations has been examined in 12 insulin-dependent diabetic patients regulated by the artificial beta-cell for 7 days. The fasting values (mean +/- SEM) of blood glucose (BG), triglycerides (TG), total cholesterol (T-chol), HDL-cholesterol (HDL), and the calculated LDL/HDL ratio (obtained while participants were on single or split insulin regimens) were 385 +/- 42 mg/dl, 148 +/- 24 mg/dl, 219 +/- 22 mg/dl, 39 +/- 3.6 mg/dl, and 3.8 +/- 1.04, respectively. Within 12 h of establishing normoglycemia TG levels fell to 87 +/- 10 mg/dl (P less than 0.001), T-chol to 196 +/- 15 mg/dl (P less than 0.005), and HDL to 37 +/- 3 mg/dl (P = NS). The LDL/HDL ratio remained unchanged. After 7 days on the artificial beta-cell, the corresponding values were: 73 +/- 5 mg/dl (P less than 0.001), 169 +/- 9 mg/dl (P less than 0.001), 41 +/- 2.6 mg/dl (P = NS), and 2.6 +/- 0.56 (P less than 0.05). Twenty-four hours after discontinuation of artificial beta-cell therapy, the TG and T-chol concentrations reverted to baseline. These findings underscore the rapidity and effectiveness with which strict control can improve plasma lipid profiles.

Adult↗

PubMedDate not supplied

Effect of intensive insulin therapy on progression of overt nephropathy in patients with type 1 diabetes mellitus.

OBJECTIVE: To assess the effects of chronic (long-term) intermittent intravenous insulin therapy (CIIIT) on the progression of overt nephropathy in patients with type 1 diabetes mellitus. METHODS: We undertook a retrospective longitudinal three-center study of 31 patients with type 1 diabetes mellitus and overt nephropathy, who were receiving intensive subcutaneous insulin therapy (four insulin injections daily) and weekly CIIIT. All study patients had follow-up consultations weekly for at least 12 months (mean duration, 37.0 +/- 4.6 months). Each patient had monthly hemoglobin A(1c) (by high-performance liquid chromatography) and semiannual creatinine clearance determinations. RESULTS: The hemoglobin A(1c) levels declined significantly from 8.6 +/- 0.6% to 7.6 +/- 0.3% (P = 0.0062) during the study period. The creatinine clearance remained essentially unchanged (from 46.1 +/- 3.0 mL/min per 1.73 m 2 at baseline to 46.0 +/- 3.9 mL/min per 1.73 m 2 at the end of the observation period, with an average annualized slope increase of 3.39 +/- 1.5 mL/min per year--no significant difference). CONCLUSION: The addition of CIIIT to intensive subcutaneous insulin therapy in patients with type 1 diabetes mellitus seems to arrest or appreciably reduce the progression of overt diabetic nephropathy, as well as substantially improve their glycemic control.

Journal Article↗

PubMedDate not supplied

Prevalence of osteoporosis in women: variation with skeletal site of measurement of bone mineral density.

OBJECTIVE: To determine retrospectively the prevalence of osteoporosis in a referral population of female patients and to compare the sensitivity for diagnosing osteoporosis by dual-energy x-ray absorptiometry (DXA) measurements of bone mineral density (BMD) at multiple skeletal sites. METHODS: We studied the data from 625 consecutive women (mean age, 57.3 +/- 13.9 years), who had been referred to our center for lumbar spine (anteroposterior [AP] and lateral region) and hip (femoral neck [FN], Ward's triangle [WT], trochanter, intertrochanteric region, and total hip) BMD measurements with use of DXA (Hologic QDR-2000) between June 1994 and July 1998. RESULTS: Osteoporosis (based on the World Health Organization definition--T-score of -2.5 or lower for BMD) was diagnosed by DXA at the following sites: AP spine in 21.7%, lateral spine in 43.2%, FN in 33.6%, WT in 49.1%, trochanter in 26.1%, intertrochanteric region in 25.9%, and total hip in 28.4% of study patients. Significant site differences were found in the prevalence of osteoporosis between the lateral and AP spine (P < 0.001), as well as between WT and the FN, trochanter, intertrochanteric region, and total hip (P < 0.001). In a subgroup of 71 women, forearm (ultradistal radius and radius 1/3 region) BMD results indicated low sensitivity for diagnosing osteoporosis, similar to that seen at the AP spine, trochanter, and intertrochanteric region. Not surprisingly, the prevalence of osteoporosis increased with advancing age (15.5% in patients younger than 50 years, in comparison with 59.6% in those older than 69 years of age). The frequency of misclassification of patients (osteoporosis at one site and normal BMD at another) with use of the seven measurement sites was 16.6% (104 of the 625 patients). CONCLUSIONS: For diagnosis of osteoporosis, DXA BMD measurements are significantly more sensitive at the lateral spine than at the AP spine, as well as at WT than at the FN, trochanter, intertrochanteric region, and total hip sites.

Absorptiometry, Photon↗

PubMedDate not supplied

Microvascular abnormalities in the bulbar conjunctiva of patients with type 2 diabetes mellitus.

OBJECTIVE: To study and quantify microvascular abnormalities objectively in vivo in patients with type 2 diabetes mellitus (T2DM). METHODS: The conjunctival microcirculation in 14 patients with T2DM and in age-matched healthy control subjects without diabetes was videotaped and objectively studied by using computer-assisted intravital microscopy (CAIM), a novel and quantitative real-time technology. RESULTS: Patients with T2DM (N = 14) had significantly (P<0.01) wider conjunctival vessel diameters (71.9 +/- 5.2 mm) than did healthy nondiabetic control subjects (54.0 +/- 4.4 mm). In the study patients, microvascular distribution was significantly (P<0.01) abnormal (36.7 +/- 18.2 versus 45.3 +/- 9.6 cm per unit area, patients versus control subjects), and vessel distribution was uneven on the surface of the bulbar conjunctiva. The arteriole:venule (A:V) ratio in patients with T2DM was extremely variable and differed significantly (P<0.01) from that in the nondiabetic control subjects (A:V approximately 1:2). In addition, a unique sinusoidal (hypertensive) vascular pattern frequently existed in some of the large veins of all study patients with T2DM but in none of the nondiabetic control subjects. CONCLUSION: We identified the presence of microvascular changes (abnormalities) in the conjunctival microcirculation of patients with T2DM. Although all these abnormalities did not appear in the same patient at the same time, the sum total of their presence in each patient correlated significantly with disease severity, as noted in the medical records. The severity of microvascular abnormalities, however, did not correlate with the duration of the disease since diagnosis. CAIM may be a useful objective and quantitative technique for assessing microangiopathy in patients with T2DM. The easy noninvasive accessibility of the conjunctival vessels and the ability to identify and locate the same vessels repeatedly for longitudinal evaluations further emphasize the usefulness of this real-time technology.

Adult↗