Rapamycin-induced impaired wound healing is associated with compromised tissue lactate accumulation and extracellular matrix remodeling.

INTRODUCTION: Extracellular matrix (ECM) remodeling involving matrix metalloproteinases (MMPs) and wound lactate accumulation are essential elements of tissue repair. The aim of this study was to investigate whether rapamycin-induced impaired healing is associated with compromised wound fluid lactate accumulation and altered ECM remodeling. METHODS: Polyvinyl alcohol sponges were subcutaneously implanted in male C57/BL6 mice. Animals were randomized to daily intraperitoneal treatment with either vehicle or 1.5 mg/kg rapamycin. After 7 or 14 days, sponges were harvested to collect wound fluid for subsequent analyses. Wounds were excised for assessment of tensile strength. RESULTS: After 7 days, wound hydroxyproline content was significantly decreased due to rapamycin therapy, whereas the observed difference in tensile strength marginally failed to show statistical significance. In addition, rapamycin reduced wound lactate accumulation and enhanced MMP-2 protein expression, and both MMP-2 and MMP-9 activity. At day 14, wound tensile strength and hydroxyproline content were significantly lower along with an increase in MMP-2 and MMP-9 activity in rapamycin-treated mice. Similarly, wound fluid lactate concentration and MMP-2 protein expression were found to be persistently decreased and increased, respectively. CONCLUSIONS: Rapamycin affects tissue repair by interfering with fundamental mechanisms involved in healing, namely lactate accumulation and ECM remodeling.

Wound fluid lactate concentration: a helpful marker for diagnosing soft-tissue infection in diabetic foot ulcers? Preliminary findings.

AIMS: To investigate the impact of wound fluid lactate concentration on diagnosing soft-tissue infection in diabetic foot ulcers. METHODS: Lactate concentration in wound fluid obtained from diabetic foot ulcers was determined using a lactate analyser and compared with clinical examination findings. RESULTS: Overall median wound fluid lactate concentration was 21.03 mm (5.58-80.40 mm). Wound lactate levels were significantly higher in infected compared with non-infected diabetic foot ulcers (P=0.001). Non-infected diabetic foot ulcers that healed within 6 months of treatment showed a significantly lower wound fluid lactate concentration at baseline as opposed to those that did not heal (P=0.007). CONCLUSIONS: Non-healing diabetic foot ulcers are characterized by high wound fluid lactate levels. Assessment of wound fluid lactate concentration might be helpful for confirming the suspicion of soft tissue infection, particularly when clinical signs are atypical.

Lactate down-regulates cellular poly(ADP-ribose) formation in cultured human skin fibroblasts.

BACKGROUND: Polyadenosine diphosphate-ribose (poly(ADP-ribose)) is a nuclear polymer which is derived from nicotinamide adenine dinucleotide (NAD(+)) catalysed by poly(ADP-ribose) polymerase 1 (PARP-1). Aside from the well known role of poly(ADP-ribosyl)ation (pADPR) in DNA repair, pADPR is also involved in other cellular processes such as apoptosis and gene expression. However, the factors that regulate the level of pADPR are not fully elucidated. In view of the fact that healing wounds contain high concentrations of lactate (10-15 mM) and exogenous lactate reduce the NAD(+) pool in cultured fibroblasts, we propose that high lactate lowers the level of nuclear pADPR. MATERIALS AND METHODS: Neonatal human dermal fibroblasts (NHDF) were plated to subconfluence and allowed to adhere. Cells were treated with 15 mM l-lactate and pADPR production was assessed by immunofluorescence analysis using 10H antibody. Difference in pADPR production was determined by calculation of positively stained cells compared to total cell numbers. Inhibition of PARP activity was tested by treatment with 100 microM 3-aminobenzamide (3-AB). Specificity of the lactate effect on pADPR synthesis was verified by using the analogue d-lactate. The contents of nicotinamide adenine dinucleotide (NAD(+)) and its reduced form (NADH) in lactated and non-lactated cell cultures were quantified by the enzymatic cyclic assay. RESULTS: We found that exogenous l-lactate (15 mM) can significantly depress pADPR content in cultured fibroblasts. PARP-1 activity was inhibited by 3-AB and analogue d-lactate showed no effect on pADPR synthesis. NAD(+)/NADH ratio was significantly lowered in lactated compared to non-lactated cell culture. CONCLUSIONS: Exogenous l-lactate (15 mM) can depress pADPR content in cultured fibroblasts. In view of the fact that healing wounds contain such high concentrations of lactate, we propose that down regulation of pADPR is associated with elevated tissue repair via pADPR dependent gene expression. This observation is important in understanding the stimulation of lactate-mediated protein expression during wound healing.

Drooling in Parkinson's disease: a novel tool for assessment of swallow frequency.

A non-invasive way to obtain objective measurements of swallowing frequency and thus indirectly, drooling was required as part of the study 'Drooling in Parkinson's disease: objective measurement and response to therapy'. A hard disk, digital recorder was developed, for use on a laptop computer, which was capable of collecting large quantities of swallowing data from an anticipated 40 patients and 10 controls. An electric microphone was taped to the subjects' larynx for recording the swallow sounds when drinking 150 ml of water and at rest for 30 minutes. The software provides an accurate visual display of the audio-signal allowing the researcher easy access to any segment of the recording and to mark and extract the swallow events, so that swallow frequency may be efficiently and accurately ascertained. Preliminary results are presented.

Invasive, high grade transitional cell carcinoma of the bladder treated with transurethral resection. A survival analysis focusing on TUR as monotherapy.

Two hundred and fifteen consecutive patients admitted to our department between 1978 and 1988 were included in a retrospective study. Entrance criteria were transitional cell carcinoma of the bladder T1-4, Grade III-IV. Status of nodes and metastases were not recorded. Initially all patients had a macroscopically radical transurethral resection (TUR). Patients were followed with cystoscopies. Recurrent tumours were treated with repeated TUR (RE-TUR). In cases of progression to a higher T-stage or recurrences with multiple papillomas (> 10), adjuvant therapy was recommended. The patients were retrospectively allocated to three different groups. Group 1 had TUR only, Group 2 had TUR + adjuvant irradiation, and Group 3 had TUR and various adjuvant therapies (Table I). Median crude actuarial overall survival was 29 months. In Groups 1, 2 and 3, median crude survival was 37, 13 and 32 months, respectively. In the analysis, most emphasis was put on Group 1. For stages T1-4 in this group, the median survivals was 67, 19, 9 and 2 months, respectively. Differences were statistically significant (p < 0.05). T1 tumour stage seemed to predict a reduced risk of progression compared with the higher tumour stages (p = 0.05, Fisher's test). There was a tendency for females to progress less often than men, but the difference was not statistically significant. In conclusion, macroscopically radical TUR does not seem to offer the same cure rates as radical cystectomy. However, in a selected group of patients with a troublesome medical history, or for patients wishing minimal risk treatment, TUR might be a reasonable treatment modality.

[Permanent bladder catheterization]. / Permanent blaerekateterbehandling.

During a period of two months, 37 patients with permanent indwelling bladder catheters on account of incontinence of urine/retention were requested to register the inconveniences connected with the treatment. Despite the necessity of catheter changes more frequently than originally planned, urinary infection and altered sexual behaviour, the majority of patients expressed satisfaction with catheter life.

Colonic haustral pattern in relation to pressure activity and presence of diverticula.

The correlation between the haustral pattern in the sigmoid colon, on the one hand, and the pressure activity and presence of diverticula, on the other, was examined in 184 patients, subjected to both X-ray examination and sigmoid pressure measurement. No correlation was found between an increased haustral pattern and a high pressure activity. Only a special S-shaped haustral pattern showed a slight correlation to an increased pressure activity. An interpretation of colonic haustral pattern in terms of muscular activity, therefore, seems unwarranted. A significant correlation was found between an increased haustral pattern and the presence of sigmoid diverticula.

Intraluminal pressure in the sigmoid colon. I. Method and results in normal subjects.

A modified method for measurement of pressure activity in the sigmoid colon is presented, using open-ended tubes and measurement of pressure activity for 30 minutes after intravenous administration of 0.5 mg of neostigmine. The motility index in 12 normal persons was found to have median 597 with a range of 125-1169. Variation among persons exceeded the day-to-day variation significantly. Error in reading the curves was negligible.

Intraluminal pressure in the sigmoid colon. II. Patients with sigmoid diverticula and related conditions.

Patients with lower abdominal symptoms, indicating colonic disorder, were classified into predefined clinical syndromes. Two important syndromes were colicky sigmoid syndrome and chronic diverticular disease. The first one, characterized by presence of colicky lower abdominal pains but absence of colonic diverticula, probably covers what is generally referred to as 'irritable bowel syndrome'. The second one was characterized by presence of lower abdominal colics and of colonic diverticula. The results showed a significant correlation between the presence of lower abdominal colics and a high pressure activity in the sigmoid colon after intravenous neostigmine. There was, however, no correlation between the presence of diverticula and a high pressure activity. The generally accepted theory of a high pressure activity as the dominant factor in the pathogenesis of colonic diverticula, therefore, was questioned, as was the equally accepted theory of a gradual development of chronic diverticular disease from the adiverticular colicky sigmoid syndrome.